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（九）c#Winform自定义控件-树-HZHControls

官网

http://www.hzhcontrols.com

前提

入行已经7,8年了，一直想做一套漂亮点的自定义控件，于是就有了本系列文章。

GitHub：https://github.com/kwwwvagaa/NetWinformControl

码云：https://gitee.com/kwwwvagaa/net_winform_custom_control.git

如果觉得写的还行，请点个 star 支持一下吧

欢迎前来交流探讨：企鹅群568015492

准备工作

对原始树控件treeview进行扩展以更改样式

先了解一下我们需要哪些功能，控件ain可以更改整好颜色，行高，选中效果，分割线等

开始

添加组件，命名TreeViewEx 继承TreeView

先看下属性

  1  private const int WS_VSCROLL = 2097152;
  2 
  3         private const int GWL_STYLE = -16;
  4 
  5         private Dictionary<string, string> _lstTips = new Dictionary<string, string>();
  6 
  7         private Font _tipFont = new Font("Arial Unicode MS", 12f);
  8 
  9         private Image _tipImage = Resources.tips;
 10 
 11         private bool _isShowTip = false;
 12 
 13         private bool _isShowByCustomModel = true;
 14 
 15         private int _nodeHeight = 50;
 16 
 17         private Image _nodeDownPic = Resources.list_add;
 18 
 19         private Image _nodeUpPic = Resources.list_subtract;
 20 
 21         private Color _nodeBackgroundColor = Color.FromArgb(61, 60, 66);
 22 
 23         private Color _nodeForeColor = Color.White;
 24 
 25         private bool _nodeIsShowSplitLine = false;
 26 
 27         private Color _nodeSplitLineColor = Color.FromArgb(54, 53, 58);
 28 
 29         private Color m_nodeSelectedColor = Color.FromArgb(255, 121, 74);
 30 
 31         private Color m_nodeSelectedForeColor = Color.White;
 32 
 33         private bool _parentNodeCanSelect = true;
 34 
 35         private SizeF treeFontSize = SizeF.Empty;
 36 
 37         private bool blnHasVBar = false;
 38 
 39         public Dictionary<string, string> LstTips
 40         {
 41             get
 42             {
 43                 return this._lstTips;
 44             }
 45             set
 46             {
 47                 this._lstTips = value;
 48             }
 49         }
 50 
 51         [Category("自定义属性"), Description("角标文字字体")]
 52         public Font TipFont
 53         {
 54             get
 55             {
 56                 return this._tipFont;
 57             }
 58             set
 59             {
 60                 this._tipFont = value;
 61             }
 62         }
 63 
 64         [Category("自定义属性"), Description("是否显示角标")]
 65         public Image TipImage
 66         {
 67             get
 68             {
 69                 return this._tipImage;
 70             }
 71             set
 72             {
 73                 this._tipImage = value;
 74             }
 75         }
 76 
 77         [Category("自定义属性"), Description("是否显示角标")]
 78         public bool IsShowTip
 79         {
 80             get
 81             {
 82                 return this._isShowTip;
 83             }
 84             set
 85             {
 86                 this._isShowTip = value;
 87             }
 88         }
 89 
 90         [Category("自定义属性"), Description("使用自定义模式")]
 91         public bool IsShowByCustomModel
 92         {
 93             get
 94             {
 95                 return this._isShowByCustomModel;
 96             }
 97             set
 98             {
 99                 this._isShowByCustomModel = value;
100             }
101         }
102 
103         [Category("自定义属性"), Description("节点高度（IsShowByCustomModel=true时生效）")]
104         public int NodeHeight
105         {
106             get
107             {
108                 return this._nodeHeight;
109             }
110             set
111             {
112                 this._nodeHeight = value;
113                 base.ItemHeight = value;
114             }
115         }
116 
117         [Category("自定义属性"), Description("下翻图标（IsShowByCustomModel=true时生效）")]
118         public Image NodeDownPic
119         {
120             get
121             {
122                 return this._nodeDownPic;
123             }
124             set
125             {
126                 this._nodeDownPic = value;
127             }
128         }
129 
130         [Category("自定义属性"), Description("上翻图标（IsShowByCustomModel=true时生效）")]
131         public Image NodeUpPic
132         {
133             get
134             {
135                 return this._nodeUpPic;
136             }
137             set
138             {
139                 this._nodeUpPic = value;
140             }
141         }
142 
143         [Category("自定义属性"), Description("节点背景颜色（IsShowByCustomModel=true时生效）")]
144         public Color NodeBackgroundColor
145         {
146             get
147             {
148                 return this._nodeBackgroundColor;
149             }
150             set
151             {
152                 this._nodeBackgroundColor = value;
153             }
154         }
155 
156         [Category("自定义属性"), Description("节点字体颜色（IsShowByCustomModel=true时生效）")]
157         public Color NodeForeColor
158         {
159             get
160             {
161                 return this._nodeForeColor;
162             }
163             set
164             {
165                 this._nodeForeColor = value;
166             }
167         }
168 
169         [Category("自定义属性"), Description("节点是否显示分割线（IsShowByCustomModel=true时生效）")]
170         public bool NodeIsShowSplitLine
171         {
172             get
173             {
174                 return this._nodeIsShowSplitLine;
175             }
176             set
177             {
178                 this._nodeIsShowSplitLine = value;
179             }
180         }
181 
182         [Category("自定义属性"), Description("节点分割线颜色（IsShowByCustomModel=true时生效）")]
183         public Color NodeSplitLineColor
184         {
185             get
186             {
187                 return this._nodeSplitLineColor;
188             }
189             set
190             {
191                 this._nodeSplitLineColor = value;
192             }
193         }
194 
195         [Category("自定义属性"), Description("选中节点背景颜色（IsShowByCustomModel=true时生效）")]
196         public Color NodeSelectedColor
197         {
198             get
199             {
200                 return this.m_nodeSelectedColor;
201             }
202             set
203             {
204                 this.m_nodeSelectedColor = value;
205             }
206         }
207 
208         [Category("自定义属性"), Description("选中节点字体颜色（IsShowByCustomModel=true时生效）")]
209         public Color NodeSelectedForeColor
210         {
211             get
212             {
213                 return this.m_nodeSelectedForeColor;
214             }
215             set
216             {
217                 this.m_nodeSelectedForeColor = value;
218             }
219         }
220 
221         [Category("自定义属性"), Description("父节点是否可选中")]
222         public bool ParentNodeCanSelect
223         {
224             get
225             {
226                 return this._parentNodeCanSelect;
227             }
228             set
229             {
230                 this._parentNodeCanSelect = value;
231             }
232         }

样式的更改主要通过节点的重绘，我们使用DrawNode事件来完成

  1  base.DrawNode += new DrawTreeNodeEventHandler(this.treeview_DrawNode);
  2 
  3 private void treeview_DrawNode(object sender, DrawTreeNodeEventArgs e)
  4         {
  5             try
  6             {
  7                 if (e.Node == null || !this._isShowByCustomModel || (e.Node.Bounds.Width <= 0 && e.Node.Bounds.Height <= 0 && e.Node.Bounds.X <= 0 && e.Node.Bounds.Y <= 0))
  8                 {
  9                     e.DrawDefault = true;
 10                 }
 11                 else
 12                 {
 13                     if (base.Nodes.IndexOf(e.Node) == 0)
 14                     {
 15                         this.blnHasVBar = this.IsVerticalScrollBarVisible();
 16                     }
 17                     Font font = e.Node.NodeFont;
 18                     if (font == null)
 19                     {
 20                         font = ((TreeView)sender).Font;
 21                     }
 22                     if (this.treeFontSize == SizeF.Empty)
 23                     {
 24                         this.treeFontSize = this.GetFontSize(font, e.Graphics);
 25                     }
 26                     bool flag = false;
 27                     int num = 0;
 28                     if (base.ImageList != null && base.ImageList.Images.Count > 0 && e.Node.ImageIndex >= 0 && e.Node.ImageIndex < base.ImageList.Images.Count)
 29                     {
 30                         flag = true;
 31                         num = (e.Bounds.Height - base.ImageList.ImageSize.Height) / 2;
 32                     }
 33                     if ((e.State == TreeNodeStates.Selected || e.State == TreeNodeStates.Focused || e.State == (TreeNodeStates.Focused | TreeNodeStates.Selected)) && (this._parentNodeCanSelect || e.Node.Nodes.Count <= 0))
 34                     {
 35                         e.Graphics.FillRectangle(new SolidBrush(this.m_nodeSelectedColor), new Rectangle(new Point(0, e.Node.Bounds.Y), new Size(base.Width, e.Node.Bounds.Height)));
 36                         e.Graphics.DrawString(e.Node.Text, font, new SolidBrush(this.m_nodeSelectedForeColor), (float)e.Bounds.X, (float)e.Bounds.Y + ((float)this._nodeHeight - this.treeFontSize.Height) / 2f);
 37                     }
 38                     else
 39                     {
 40                         e.Graphics.FillRectangle(new SolidBrush(this._nodeBackgroundColor), new Rectangle(new Point(0, e.Node.Bounds.Y), new Size(base.Width, e.Node.Bounds.Height)));
 41                         e.Graphics.DrawString(e.Node.Text, font, new SolidBrush(this._nodeForeColor), (float)e.Bounds.X, (float)e.Bounds.Y + ((float)this._nodeHeight - this.treeFontSize.Height) / 2f);
 42                     }
 43                     if (flag)
 44                     {
 45                         int num2 = e.Bounds.X - num - base.ImageList.ImageSize.Width;
 46                         if (num2 < 0)
 47                         {
 48                             num2 = 3;
 49                         }
 50                         e.Graphics.DrawImage(base.ImageList.Images[e.Node.ImageIndex], new Rectangle(new Point(num2, e.Bounds.Y + num), base.ImageList.ImageSize));
 51                     }
 52                     if (this._nodeIsShowSplitLine)
 53                     {
 54                         e.Graphics.DrawLine(new Pen(this._nodeSplitLineColor, 1f), new Point(0, e.Bounds.Y + this._nodeHeight - 1), new Point(base.Width, e.Bounds.Y + this._nodeHeight - 1));
 55                     }
 56                     bool flag2 = false;
 57                     if (e.Node.Nodes.Count > 0)
 58                     {
 59                         if (e.Node.IsExpanded && this._nodeUpPic != null)
 60                         {
 61                             e.Graphics.DrawImage(this._nodeUpPic, new Rectangle(base.Width - (this.blnHasVBar ? 50 : 30), e.Bounds.Y + (this._nodeHeight - 20) / 2, 20, 20));
 62                         }
 63                         else if (this._nodeDownPic != null)
 64                         {
 65                             e.Graphics.DrawImage(this._nodeDownPic, new Rectangle(base.Width - (this.blnHasVBar ? 50 : 30), e.Bounds.Y + (this._nodeHeight - 20) / 2, 20, 20));
 66                         }
 67                         flag2 = true;
 68                     }
 69                     if (this._isShowTip && this._lstTips.ContainsKey(e.Node.Name) && !string.IsNullOrWhiteSpace(this._lstTips[e.Node.Name]))
 70                     {
 71                         int num3 = base.Width - (this.blnHasVBar ? 50 : 30) - (flag2 ? 20 : 0);
 72                         int num4 = e.Bounds.Y + (this._nodeHeight - 20) / 2;
 73                         e.Graphics.DrawImage(this._tipImage, new Rectangle(num3, num4, 20, 20));
 74                         SizeF sizeF = e.Graphics.MeasureString(this._lstTips[e.Node.Name], this._tipFont, 100, StringFormat.GenericTypographic);
 75                         e.Graphics.DrawString(this._lstTips[e.Node.Name], this._tipFont, new SolidBrush(Color.White), (float)(num3 + 10) - sizeF.Width / 2f - 3f, (float)(num4 + 10) - sizeF.Height / 2f);
 76                     }
 77                 }
 78             }
 79             catch (Exception ex)
 80             {
 81                 throw ex;
 82             }
 83         }
 84 
 85         private SizeF GetFontSize(Font font, Graphics g = null)
 86         {
 87             SizeF result;
 88             try
 89             {
 90                 bool flag = false;
 91                 if (g == null)
 92                 {
 93                     g = base.CreateGraphics();
 94                     flag = true;
 95                 }
 96                 SizeF sizeF = g.MeasureString("a", font, 100, StringFormat.GenericTypographic);
 97                 if (flag)
 98                 {
 99                     g.Dispose();
100                 }
101                 result = sizeF;
102             }
103             catch (Exception ex)
104             {
105                 throw ex;
106             }
107             return result;
108         }
109 
110         [DllImport("user32", CharSet = CharSet.Auto)]
111         private static extern int GetWindowLong(IntPtr hwnd, int nIndex);
112 
113         private bool IsVerticalScrollBarVisible()
114         {
115             return base.IsHandleCreated && (TreeViewEx.GetWindowLong(base.Handle, -16) & 2097152) != 0;
116         }

我们还需要对选中节点时做一些处理

 1 private void TreeViewEx_NodeMouseClick(object sender, TreeNodeMouseClickEventArgs e)
 2         {
 3             try
 4             {
 5                 if (e.Node != null)
 6                 {
 7                     if (e.Node.Nodes.Count > 0)
 8                     {
 9                         if (e.Node.IsExpanded)
10                         {
11                             e.Node.Collapse();
12                         }
13                         else
14                         {
15                             e.Node.Expand();
16                         }
17                     }
18                     if (base.SelectedNode != null)
19                     {
20                         if (base.SelectedNode == e.Node && e.Node.IsExpanded)
21                         {
22                             if (!this._parentNodeCanSelect)
23                             {
24                                 if (e.Node.Nodes.Count > 0)
25                                 {
26                                     base.SelectedNode = e.Node.Nodes[0];
27                                 }
28                             }
29                         }
30                     }
31                 }
32             }
33             catch (Exception ex)
34             {
35                 throw ex;
36             }
37         }

选中后也需要根据属性做相应的操作

 1  private void TreeViewEx_AfterSelect(object sender, TreeViewEventArgs e)
 2         {
 3             try
 4             {
 5                 if (e.Node != null)
 6                 {
 7                     if (!this._parentNodeCanSelect)
 8                     {
 9                         if (e.Node.Nodes.Count > 0)
10                         {
11                             e.Node.Expand();
12                             base.SelectedNode = e.Node.Nodes[0];
13                         }
14                     }
15                 }
16             }
17             catch (Exception ex)
18             {
19                 throw ex;
20             }
21         }

主要的东西就这些了，我们看下完成的代码吧

  1 // 版权所有  黄正辉  交流群：568015492   QQ：623128629
  2 // 文件名称：TreeViewEx.cs
  3 // 创建日期：2019-08-15 16:00:55
  4 // 功能描述：TreeView
  5 // 项目地址：https://gitee.com/kwwwvagaa/net_winform_custom_control
  6 
  7 using System;
  8 using System.Collections.Generic;
  9 using System.ComponentModel;
 10 using System.Diagnostics;
 11 using System.Drawing;
 12 using System.Linq;
 13 using System.Runtime.InteropServices;
 14 using System.Text;
 15 using System.Windows.Forms;
 16 using HZH_Controls.Properties;
 17 
 18 namespace HZH_Controls.Controls
 19 {
 20     public partial class TreeViewEx : TreeView
 21     {
 22 
 23         private const int WS_VSCROLL = 2097152;
 24 
 25         private const int GWL_STYLE = -16;
 26 
 27         private Dictionary<string, string> _lstTips = new Dictionary<string, string>();
 28 
 29         private Font _tipFont = new Font("Arial Unicode MS", 12f);
 30 
 31         private Image _tipImage = Resources.tips;
 32 
 33         private bool _isShowTip = false;
 34 
 35         private bool _isShowByCustomModel = true;
 36 
 37         private int _nodeHeight = 50;
 38 
 39         private Image _nodeDownPic = Resources.list_add;
 40 
 41         private Image _nodeUpPic = Resources.list_subtract;
 42 
 43         private Color _nodeBackgroundColor = Color.FromArgb(61, 60, 66);
 44 
 45         private Color _nodeForeColor = Color.White;
 46 
 47         private bool _nodeIsShowSplitLine = false;
 48 
 49         private Color _nodeSplitLineColor = Color.FromArgb(54, 53, 58);
 50 
 51         private Color m_nodeSelectedColor = Color.FromArgb(255, 121, 74);
 52 
 53         private Color m_nodeSelectedForeColor = Color.White;
 54 
 55         private bool _parentNodeCanSelect = true;
 56 
 57         private SizeF treeFontSize = SizeF.Empty;
 58 
 59         private bool blnHasVBar = false;
 60 
 61         public Dictionary<string, string> LstTips
 62         {
 63             get
 64             {
 65                 return this._lstTips;
 66             }
 67             set
 68             {
 69                 this._lstTips = value;
 70             }
 71         }
 72 
 73         [Category("自定义属性"), Description("角标文字字体")]
 74         public Font TipFont
 75         {
 76             get
 77             {
 78                 return this._tipFont;
 79             }
 80             set
 81             {
 82                 this._tipFont = value;
 83             }
 84         }
 85 
 86         [Category("自定义属性"), Description("是否显示角标")]
 87         public Image TipImage
 88         {
 89             get
 90             {
 91                 return this._tipImage;
 92             }
 93             set
 94             {
 95                 this._tipImage = value;
 96             }
 97         }
 98 
 99         [Category("自定义属性"), Description("是否显示角标")]
100         public bool IsShowTip
101         {
102             get
103             {
104                 return this._isShowTip;
105             }
106             set
107             {
108                 this._isShowTip = value;
109             }
110         }
111 
112         [Category("自定义属性"), Description("使用自定义模式")]
113         public bool IsShowByCustomModel
114         {
115             get
116             {
117                 return this._isShowByCustomModel;
118             }
119             set
120             {
121                 this._isShowByCustomModel = value;
122             }
123         }
124 
125         [Category("自定义属性"), Description("节点高度（IsShowByCustomModel=true时生效）")]
126         public int NodeHeight
127         {
128             get
129             {
130                 return this._nodeHeight;
131             }
132             set
133             {
134                 this._nodeHeight = value;
135                 base.ItemHeight = value;
136             }
137         }
138 
139         [Category("自定义属性"), Description("下翻图标（IsShowByCustomModel=true时生效）")]
140         public Image NodeDownPic
141         {
142             get
143             {
144                 return this._nodeDownPic;
145             }
146             set
147             {
148                 this._nodeDownPic = value;
149             }
150         }
151 
152         [Category("自定义属性"), Description("上翻图标（IsShowByCustomModel=true时生效）")]
153         public Image NodeUpPic
154         {
155             get
156             {
157                 return this._nodeUpPic;
158             }
159             set
160             {
161                 this._nodeUpPic = value;
162             }
163         }
164 
165         [Category("自定义属性"), Description("节点背景颜色（IsShowByCustomModel=true时生效）")]
166         public Color NodeBackgroundColor
167         {
168             get
169             {
170                 return this._nodeBackgroundColor;
171             }
172             set
173             {
174                 this._nodeBackgroundColor = value;
175             }
176         }
177 
178         [Category("自定义属性"), Description("节点字体颜色（IsShowByCustomModel=true时生效）")]
179         public Color NodeForeColor
180         {
181             get
182             {
183                 return this._nodeForeColor;
184             }
185             set
186             {
187                 this._nodeForeColor = value;
188             }
189         }
190 
191         [Category("自定义属性"), Description("节点是否显示分割线（IsShowByCustomModel=true时生效）")]
192         public bool NodeIsShowSplitLine
193         {
194             get
195             {
196                 return this._nodeIsShowSplitLine;
197             }
198             set
199             {
200                 this._nodeIsShowSplitLine = value;
201             }
202         }
203 
204         [Category("自定义属性"), Description("节点分割线颜色（IsShowByCustomModel=true时生效）")]
205         public Color NodeSplitLineColor
206         {
207             get
208             {
209                 return this._nodeSplitLineColor;
210             }
211             set
212             {
213                 this._nodeSplitLineColor = value;
214             }
215         }
216 
217         [Category("自定义属性"), Description("选中节点背景颜色（IsShowByCustomModel=true时生效）")]
218         public Color NodeSelectedColor
219         {
220             get
221             {
222                 return this.m_nodeSelectedColor;
223             }
224             set
225             {
226                 this.m_nodeSelectedColor = value;
227             }
228         }
229 
230         [Category("自定义属性"), Description("选中节点字体颜色（IsShowByCustomModel=true时生效）")]
231         public Color NodeSelectedForeColor
232         {
233             get
234             {
235                 return this.m_nodeSelectedForeColor;
236             }
237             set
238             {
239                 this.m_nodeSelectedForeColor = value;
240             }
241         }
242 
243         [Category("自定义属性"), Description("父节点是否可选中")]
244         public bool ParentNodeCanSelect
245         {
246             get
247             {
248                 return this._parentNodeCanSelect;
249             }
250             set
251             {
252                 this._parentNodeCanSelect = value;
253             }
254         }
255         public TreeViewEx()
256         {
257             base.HideSelection = false;
258             base.DrawMode = TreeViewDrawMode.OwnerDrawAll;
259             base.DrawNode += new DrawTreeNodeEventHandler(this.treeview_DrawNode);
260             base.NodeMouseClick += new TreeNodeMouseClickEventHandler(this.TreeViewEx_NodeMouseClick);
261             base.SizeChanged += new EventHandler(this.TreeViewEx_SizeChanged);
262             base.AfterSelect += new TreeViewEventHandler(this.TreeViewEx_AfterSelect);
263             base.FullRowSelect = true;
264             base.ShowLines = false;
265             base.ShowPlusMinus = false;
266             base.ShowRootLines = false;
267             this.BackColor = Color.FromArgb(61, 60, 66);
268             DoubleBuffered = true;
269         }
270         protected override void WndProc(ref Message m)
271         {
272 
273             if (m.Msg == 0x0014) // 禁掉清除背景消息WM_ERASEBKGND
274 
275                 return;
276 
277             base.WndProc(ref m);
278 
279         }
280         private void TreeViewEx_AfterSelect(object sender, TreeViewEventArgs e)
281         {
282             try
283             {
284                 if (e.Node != null)
285                 {
286                     if (!this._parentNodeCanSelect)
287                     {
288                         if (e.Node.Nodes.Count > 0)
289                         {
290                             e.Node.Expand();
291                             base.SelectedNode = e.Node.Nodes[0];
292                         }
293                     }
294                 }
295             }
296             catch (Exception ex)
297             {
298                 throw ex;
299             }
300         }
301 
302         private void TreeViewEx_SizeChanged(object sender, EventArgs e)
303         {
304             this.Refresh();
305         }
306 
307         private void TreeViewEx_NodeMouseClick(object sender, TreeNodeMouseClickEventArgs e)
308         {
309             try
310             {
311                 if (e.Node != null)
312                 {
313                     if (e.Node.Nodes.Count > 0)
314                     {
315                         if (e.Node.IsExpanded)
316                         {
317                             e.Node.Collapse();
318                         }
319                         else
320                         {
321                             e.Node.Expand();
322                         }
323                     }
324                     if (base.SelectedNode != null)
325                     {
326                         if (base.SelectedNode == e.Node && e.Node.IsExpanded)
327                         {
328                             if (!this._parentNodeCanSelect)
329                             {
330                                 if (e.Node.Nodes.Count > 0)
331                                 {
332                                     base.SelectedNode = e.Node.Nodes[0];
333                                 }
334                             }
335                         }
336                     }
337                 }
338             }
339             catch (Exception ex)
340             {
341                 throw ex;
342             }
343         }
344 
345         private void treeview_DrawNode(object sender, DrawTreeNodeEventArgs e)
346         {
347             try
348             {
349                 if (e.Node == null || !this._isShowByCustomModel || (e.Node.Bounds.Width <= 0 && e.Node.Bounds.Height <= 0 && e.Node.Bounds.X <= 0 && e.Node.Bounds.Y <= 0))
350                 {
351                     e.DrawDefault = true;
352                 }
353                 else
354                 {
355                     if (base.Nodes.IndexOf(e.Node) == 0)
356                     {
357                         this.blnHasVBar = this.IsVerticalScrollBarVisible();
358                     }
359                     Font font = e.Node.NodeFont;
360                     if (font == null)
361                     {
362                         font = ((TreeView)sender).Font;
363                     }
364                     if (this.treeFontSize == SizeF.Empty)
365                     {
366                         this.treeFontSize = this.GetFontSize(font, e.Graphics);
367                     }
368                     bool flag = false;
369                     int num = 0;
370                     if (base.ImageList != null && base.ImageList.Images.Count > 0 && e.Node.ImageIndex >= 0 && e.Node.ImageIndex < base.ImageList.Images.Count)
371                     {
372                         flag = true;
373                         num = (e.Bounds.Height - base.ImageList.ImageSize.Height) / 2;
374                     }
375                     if ((e.State == TreeNodeStates.Selected || e.State == TreeNodeStates.Focused || e.State == (TreeNodeStates.Focused | TreeNodeStates.Selected)) && (this._parentNodeCanSelect || e.Node.Nodes.Count <= 0))
376                     {
377                         e.Graphics.FillRectangle(new SolidBrush(this.m_nodeSelectedColor), new Rectangle(new Point(0, e.Node.Bounds.Y), new Size(base.Width, e.Node.Bounds.Height)));
378                         e.Graphics.DrawString(e.Node.Text, font, new SolidBrush(this.m_nodeSelectedForeColor), (float)e.Bounds.X, (float)e.Bounds.Y + ((float)this._nodeHeight - this.treeFontSize.Height) / 2f);
379                     }
380                     else
381                     {
382                         e.Graphics.FillRectangle(new SolidBrush(this._nodeBackgroundColor), new Rectangle(new Point(0, e.Node.Bounds.Y), new Size(base.Width, e.Node.Bounds.Height)));
383                         e.Graphics.DrawString(e.Node.Text, font, new SolidBrush(this._nodeForeColor), (float)e.Bounds.X, (float)e.Bounds.Y + ((float)this._nodeHeight - this.treeFontSize.Height) / 2f);
384                     }
385                     if (flag)
386                     {
387                         int num2 = e.Bounds.X - num - base.ImageList.ImageSize.Width;
388                         if (num2 < 0)
389                         {
390                             num2 = 3;
391                         }
392                         e.Graphics.DrawImage(base.ImageList.Images[e.Node.ImageIndex], new Rectangle(new Point(num2, e.Bounds.Y + num), base.ImageList.ImageSize));
393                     }
394                     if (this._nodeIsShowSplitLine)
395                     {
396                         e.Graphics.DrawLine(new Pen(this._nodeSplitLineColor, 1f), new Point(0, e.Bounds.Y + this._nodeHeight - 1), new Point(base.Width, e.Bounds.Y + this._nodeHeight - 1));
397                     }
398                     bool flag2 = false;
399                     if (e.Node.Nodes.Count > 0)
400                     {
401                         if (e.Node.IsExpanded && this._nodeUpPic != null)
402                         {
403                             e.Graphics.DrawImage(this._nodeUpPic, new Rectangle(base.Width - (this.blnHasVBar ? 50 : 30), e.Bounds.Y + (this._nodeHeight - 20) / 2, 20, 20));
404                         }
405                         else if (this._nodeDownPic != null)
406                         {
407                             e.Graphics.DrawImage(this._nodeDownPic, new Rectangle(base.Width - (this.blnHasVBar ? 50 : 30), e.Bounds.Y + (this._nodeHeight - 20) / 2, 20, 20));
408                         }
409                         flag2 = true;
410                     }
411                     if (this._isShowTip && this._lstTips.ContainsKey(e.Node.Name) && !string.IsNullOrWhiteSpace(this._lstTips[e.Node.Name]))
412                     {
413                         int num3 = base.Width - (this.blnHasVBar ? 50 : 30) - (flag2 ? 20 : 0);
414                         int num4 = e.Bounds.Y + (this._nodeHeight - 20) / 2;
415                         e.Graphics.DrawImage(this._tipImage, new Rectangle(num3, num4, 20, 20));
416                         SizeF sizeF = e.Graphics.MeasureString(this._lstTips[e.Node.Name], this._tipFont, 100, StringFormat.GenericTypographic);
417                         e.Graphics.DrawString(this._lstTips[e.Node.Name], this._tipFont, new SolidBrush(Color.White), (float)(num3 + 10) - sizeF.Width / 2f - 3f, (float)(num4 + 10) - sizeF.Height / 2f);
418                     }
419                 }
420             }
421             catch (Exception ex)
422             {
423                 throw ex;
424             }
425         }
426 
427         private SizeF GetFontSize(Font font, Graphics g = null)
428         {
429             SizeF result;
430             try
431             {
432                 bool flag = false;
433                 if (g == null)
434                 {
435                     g = base.CreateGraphics();
436                     flag = true;
437                 }
438                 SizeF sizeF = g.MeasureString("a", font, 100, StringFormat.GenericTypographic);
439                 if (flag)
440                 {
441                     g.Dispose();
442                 }
443                 result = sizeF;
444             }
445             catch (Exception ex)
446             {
447                 throw ex;
448             }
449             return result;
450         }
451 
452         [DllImport("user32", CharSet = CharSet.Auto)]
453         private static extern int GetWindowLong(IntPtr hwnd, int nIndex);
454 
455         private bool IsVerticalScrollBarVisible()
456         {
457             return base.IsHandleCreated && (TreeViewEx.GetWindowLong(base.Handle, -16) & 2097152) != 0;
458         }
459     }
460 }

View Code

用处及效果

用处：觉得原始的treeview太难看了，想换一种好看点的风格

效果：

调用示例

 for (int i = 0; i < 3; i++)
            {
                TreeNode tn = new TreeNode("  父节点" + i);
                for (int j = 0; j < 3; j++)
                {
                    tn.Nodes.Add("    子节点" + j);
                }
                this.treeViewEx1.Nodes.Add(tn);
            }

最后的话

如果你喜欢的话，请到 https://gitee.com/kwwwvagaa/net_winform_custom_control 点个星星吧

查看全文

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原文地址：https://www.cnblogs.com/bfyx/p/11362375.html

（九）c#Winform自定义控件-树-HZHControls

官网

前提

目录

准备工作

开始

用处及效果

最后的话