DropDownTreeList

asp.net本身就给我们提供了很多控件,而且不少控件开发公司也为我们提供了丰富漂亮的控件；但仍然不能满足我这样的懒人在实际项目中的需要,所以就需要学会自己来开发控件。因为我不想重复工作,所以要创建它,我自己是很喜欢控件开发，只不过目前还是一个小菜。
    前些时间在园子里看到有位朋友写也了一个DropDownTreeList控件,说实话写的很是不错。今天也贴出我在项目中写的DropDownTreeList控件，以此来和园子里喜欢控件开发的朋友共同进步。
    是不是有朋友在说：“少废话了，代码贴出来看看先”。好，那就贴出代码先：

  1/**//// <summary>
  2    /// 下拉树形框控件。
  3    /// </summary>
  4    [DefaultProperty("Text"), ToolboxData("<{0}:DropDownTreeList runat=server></{0}:DropDownTreeList>")]
  5    public class DropDownTreeList : WebControl, IPostBackDataHandler, IPostBackEventHandler
  6    {
  7
  8        /**//// <summary>
  9        /// 下拉列表框控件变量
 10        /// </summary>
 11        public System.Web.UI.WebControls.DropDownList TypeID = new System.Web.UI.WebControls.DropDownList();
 12
 13        
 14        /**//// <summary>
 15        /// 构造函数
 16        /// </summary>
 17        public DropDownTreeList(): base()
 18        {
 19            this.BorderStyle = BorderStyle.Groove;
 20            this.BorderWidth = 1;
 21        }
 22
 23        /**//// <summary>
 24        /// 构造函数
 25        /// </summary>
 26        /// <param name="dt"></param>
 27        public DropDownTreeList(DataTable dt): this()
 28        {
 29            BuildTree(dt);
 30        }
 31
 32        /**//// <summary>
 33        /// 构造函数
 34        /// </summary>
 35        /// <param name="selectid">选择项</param>
 36        /// <param name="dt"></param>
 37        public DropDownTreeList(string selectid,DataTable dt): this(dt)
 38        {
 39            this.TypeID.SelectedValue = selectid;
 40        }
 41
 42        /**//// <summary>
 43        /// 创建树
 44        /// </summary>
 45        /// <param name="dt"></param>
 46        public void BuildTree(DataTable dt)
 47        {
 48            if(this.ParentFiledName.Trim()=="")
 49            {
 50                throw new Exception("父字段名称不能为空");
 51            }
 52            if (this.NodeTextField.Trim() == "")
 53            {
 54                throw new Exception("节点文本字段名称不能为空");
 55            }
 56            if(this.NodeValueField.Trim()=="")
 57            {
 58                throw new Exception("节点值字段名称不能为空");
 59            }
 60            string SelectedType = "0";
 61
 62            TypeID.SelectedValue = SelectedType;
 63            this.Controls.Add(TypeID);
 64            TypeID.Items.Clear();
 65            //加载树
 66            TypeID.Items.Add(new ListItem("请选择     ", "0"));
 67            DataRow[] drs = dt.Select(this.ParentFiledName + "=0");
 68            foreach (DataRow r in drs)
 69            {  
 70                TypeID.Items.Add(new ListItem(r[NodeTextField].ToString(), r[NodeValueField].ToString()));
 71                string blank=StyleDropTree.DropDownTreeList_Style(DropTreeStyle);
 72                BindNode(r[NodeValueField].ToString(), dt, blank);
 73            }
 74            
 75            TypeID.DataBind();
 76        }
 77
 78        private string _nodeValueField="";
 79        /**//// <summary>
 80        /// 节点值字段
 81        /// </summary>
 82        [Bindable(true), Browsable(true), Category("数据"), DefaultValue("")]
 83        public string NodeValueField
 84        {
 85            get
 86            {
 87                try
 88                {
 89                    return _nodeValueField;
 90                }
 91                catch
 92                {
 93                    throw new Exception();
 94                }
 95
 96            }
 97            set
 98            {
 99                this._nodeValueField = value;
100            }
101        }
102
103        private string _nodeTextField="";
104        /**//// <summary>
105        /// 节点文本字段
106        /// </summary>
107        [Bindable(true), Browsable(true), Category("数据"), DefaultValue("")]
108        public string NodeTextField
109        {
110            get
111            {
112                try
113                {
114                    return _nodeTextField;
115                }
116                catch
117                {
118                    throw new Exception();
119                }
120
121            }
122            set
123            {
124                this._nodeTextField = value;
125            }
126        }
127
128        /**//// <summary>
129        /// 创建树
130        /// </summary>
131        /// <param name="sqlstring">查询字符串</param>
132        /// <param name="selectid">选取项</param>
133        public void BuildTree(string selectid,DataTable dt)
134        {
135            BuildTree(dt);
136            this.TypeID.SelectedValue = selectid;
137        }
138
139        /**//// <summary>
140        /// 创建树结点
141        /// </summary>
142        /// <param name="sonparentid">当前数据项</param>
143        /// <param name="dt">数据表</param>
144        /// <param name="blank">空白符</param>
145        private void BindNode(string sonparentid, DataTable dt, string blank)
146        {
147            DataRow[] drs = dt.Select(this.ParentFiledName + "=" + sonparentid);
148
149            foreach (DataRow r in drs)
150            {
151                string nodevalue = r[NodeValueField].ToString();
152                string text = r[NodeTextField].ToString();
153                if (StyleDropTree.DropDownTreeList_Style(DropTreeStyle) == "├─『")
154                {
155                    text = blank + "" + text + "』";
156                }
157                else
158                {
159                    text = blank + "" + text + "";
160                }
161                TypeID.Items.Add(new ListItem(text, nodevalue));
162                string blankNode = HttpUtility.HtmlDecode("&nbsp;&nbsp;&nbsp;&nbsp;") + blank;
163                BindNode(nodevalue, dt, blankNode);
164            }
165        }
166
167        
168        /**//// <summary>
169        /// 当前选择项的值
170        /// </summary>
171        [Bindable(false), Browsable(false), Category("数据"), DefaultValue("")]
172        public string SelectedValue
173        {
174            get
175            {
176                return this.TypeID.SelectedValue;
177            }
178
179            set
180            {
181                this.TypeID.SelectedValue = value;
182            }
183        }
184        
185        /**//// <summary>
186        /// 当前选择项的文本
187        /// </summary>
188        [Bindable(false), Browsable(false), Category("数据"), DefaultValue("")]
189        public string SelectedText
190        {
191            get 
192            {
193                try
194                {
195                    string NodeText = this.TypeID.SelectedItem.Text.Trim();
196                    int i = 0;
197                    if (StyleDropTree.DropDownTreeList_Style(DropTreeStyle) == "├─『")
198                    {
199                        i = NodeText.IndexOf("『");
200                        return NodeText.Substring(i + 1, NodeText.Length - i - 2);
201                    }
202                    else
203                    {
204                        return NodeText.Trim();
205                    }
206                    
207                }
208                catch
209                {
210                    return "";
211                }
212                
213            }
214            set 
215            { 
216                this.TypeID.SelectedItem.Text=value;
217            }
218        }
219        /**//// <summary>
220        /// 父字段名称
221        /// </summary>
222        private string m_parentid = "";
223        [Bindable(true), Category("数据"), DefaultValue("")]
224        public string ParentFiledName
225        {
226            get
227            {
228                return m_parentid;
229            }
230
231            set
232            {
233                m_parentid = value;
234            }
235        }
236
237        /**//// <summary>
238        /// 当某选项被选中后,获取焦点的控件ID(如提交按钮等)
239        /// </summary>
240        [Bindable(true), Category("数据"), DefaultValue("")]
241        public string SetFocusButtonID
242        {
243            get
244            {
245                object o = ViewState[this.ClientID + "_SetFocusButtonID"];
246                return (o == null) ? "" : o.ToString();
247            }
248            set
249            {
250                ViewState[this.ClientID + "_SetFocusButtonID"] = value;
251                if (value != "")
252                {
253                    this.TypeID.Attributes.Add("onChange", "document.getElementById('" + value + "').focus();");
254                }
255            }
256        }
257
258        /**//// <summary>
259        /// 获取或设置数据源
260        /// </summary>
261        private object _dataSource;
262        [Bindable(true),Category("Data"),DefaultValue(null),Description("数据"),DesignerSerializationVisibility(DesignerSerializationVisibility.Hidden)]
263        public virtual object DataSource
264        {
265            get
266             {
267                 return _dataSource;
268             }
269            set
270            {
271                 if ((value == null) || (value is IListSource) || (value is IEnumerable))
272                {
273                    _dataSource = value;
274                }
275                else
276                {
277                    throw new ArgumentException();
278                 }
279             }
280         }
281         
282         public override void DataBind()
283         {       
284             base.OnDataBinding(EventArgs.Empty);
285             DataTable table = (DataTable)this.DataSource;
286             BuildTree(table);
287         }
288 
289
290        private StyleLook _styleLook;
291        /**//// <summary>
292        /// 设置控件的样式
293        /// </summary>
294        [Bindable(true), Category("样式"), DefaultValue("")]
295        public StyleLook DropTreeStyle
296        {
297
298            set { _styleLook = value; }
299            get { return _styleLook; }
300        }
301        /**//// <summary>
302        /// 输出html,在浏览器中显示控件
303        /// </summary>
304        /// <param name="output"> 要写出到的 HTML 编写器 </param>
305        protected override void Render(HtmlTextWriter output)
306        {
307            if (this.HintInfo != "")
308            {
309                output.WriteBeginTag("span id=\"" + this.ClientID + "\"  onmouseover=\"showhintinfo(this," + this.HintLeftOffSet + "," + this.HintTopOffSet + ",'" + this.HintTitle + "','" + this.HintInfo + "','" + this.HintHeight + "','" + this.HintShowType + "');\" onmouseout=\"hidehintinfo();\">");
310            }
311
312            RenderChildren(output);
313
314            if (this.HintInfo != "")
315            {
316                output.WriteEndTag("span");
317            }
318        }
319
320
321
322        IPostBackDataHandler 成员#region IPostBackDataHandler 成员
323
324
325        /**//// <summary>
326        /// 引发PostBackChanged事件
327        /// </summary>
328        public void RaisePostDataChangedEvent()
329        {
330        }
331
332
333        /**//// <summary>
334        /// 引发PostBack事件
335        /// </summary>
336        /// <param name="eventArgument"></param>
337        public void RaisePostBackEvent(string eventArgument)
338        {
339        }
340
341        /**//// <summary>
342        /// 加载提交数据
343        /// </summary>
344        /// <param name="postDataKey"></param>
345        /// <param name="postCollection"></param>
346        /// <returns></returns>
347        public bool LoadPostData(string postDataKey, System.Collections.Specialized.NameValueCollection postCollection)
348        {
349
350            string presentValue = this.TypeID.SelectedValue;
351            string postedValue = postCollection[postDataKey];
352
353            //如果回发数据不等于原有数据
354            if (!presentValue.Equals(postedValue))
355            {
356                //this.SqlText = postedValue;
357                return true;
358            }
359            return false;
360
361        }
362        #endregion

        “连个效果图没有，就让人看你那烂代码。来个图先？”，有朋友又在喊了。
            好的，图来了。效果1：
            好的，图来了。效果2：
           使用方法：
string SQl = "select * from SYS_T_Menu";
            DataTable dt = SqlHelper.ReturnDataTable(SQl);
            DropDownTreeList1.NodeTextField = "Menu_Name";
            DropDownTreeList1.NodeValueField = "Menu_ID";
            DropDownTreeList1.ParentFiledName = "Menu_Father_ID";
            DropDownTreeList1.DataSource = dt;
            DropDownTreeList1.DataBind();