.net C# PropertyGrid 显示下拉列表

PropertyGrid是.net的 一个功能非常强大的控件，最近因为项目中需要使用这个控件，特意关注了一下它的用法。

在我这个项目中主要用到的功能是编辑表的各种属性，效果如下：

显示这种效果实现思路可能不止一个，遗憾的是我目前只知道这一个，因为时间关系也没有仔细研究。我的方法是：

（1）先自定义一个控件继承CheckedListBox，代码如下：

using System;
using System.Collections;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Drawing.Design;
using System.Reflection;
using System.Runtime.InteropServices;
using System.Text;
using System.Windows.Forms;

namespace PropertyGridDemo
{
    public class CheckedListBoxUC : CheckedListBox
    {
        private System.Windows.Forms.Design.IWindowsFormsEditorService m_iws;

        private string m_selectStr = string.Empty;

        /// <summary>
        /// 获取选择的字段，多个字段用"|"隔开
        /// </summary>
        public string SelectedFields
        {
            get
            {
                return this.m_selectStr;
            }

        }
        public CheckedListBoxUC(System.Windows.Forms.Design.IWindowsFormsEditorService iws)
        {
            this.m_iws = iws;
            this.Visible = true;
            this.Height = 100;
            this.BorderStyle = BorderStyle.None;
            //添加事件
            this.Leave += new EventHandler(checkedListBoxUC_Leave);

            try
            {
                string[] strsFields = LayerParams.GetFields();
                this.BeginUpdate();
                this.Items.Clear();
                if (null != strsFields)
                {
                    for (int i = 0; i < strsFields.Length; i++)
                    {
                        this.Items.Add(strsFields[i]);
                    }
                }
            }
            catch (Exception ex)
            {
                MessageBox.Show(ex.Message, "错误", MessageBoxButtons.OK, MessageBoxIcon.Error);
            }
            finally
            {
                this.EndUpdate();
            }
        }

        void checkedListBoxUC_Leave(object sender, EventArgs e)
        {
            List<string> lstStrs = new List<string>();
            for (int i = 0; i < this.Items.Count; i++)
            {
                if (this.GetItemChecked(i))
                {
                    lstStrs.Add((string)this.Items[i]);
                }

            }
            m_selectStr = string.Join("|", lstStrs.ToArray());
            this.m_iws.CloseDropDown();
        }

    }
}

需要注意的是必须在这个控件的构造方法里面添加好要显示的项。

（2）自定义一个类继承System.Drawing.Design.UITypeEditor

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Drawing.Design;
using System.Linq;
using System.Text;

namespace PropertyGridDemo
{
    public class ListBoxUCConverter : System.Drawing.Design.UITypeEditor
    {
        public override UITypeEditorEditStyle GetEditStyle(ITypeDescriptorContext context)
        {
            return System.Drawing.Design.UITypeEditorEditStyle.DropDown;
        }

        public override object EditValue(ITypeDescriptorContext context, IServiceProvider provider, object value)
        {
            System.Windows.Forms.Design.IWindowsFormsEditorService iws = (System.Windows.Forms.Design.IWindowsFormsEditorService)provider.GetService(typeof(System.Windows.Forms.Design.IWindowsFormsEditorService));
            if (iws != null)
            {
                ListBoxUC chkListBoxUC = new ListBoxUC(iws);
                iws.DropDownControl(chkListBoxUC);
                return chkListBoxUC.SelectedField;
            }
            return value;
        }
    }
}

(3)在一个类的属性中使用ListBoxConverter类

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Linq;
using System.Text;

namespace PropertyGridDemo
{
    public class AtbDataRuleProps:RuleProps
    {
        protected string m_strFields = string.Empty;

        public AtbDataRuleProps()
        { }


        [CategoryAttribute("常规"), DescriptionAttribute("检查字段"), EditorAttribute(typeof(CheckedListBoxUCConverter), typeof(System.Drawing.Design.UITypeEditor))]
        public string Fields
        {
            get
            {
                return m_strFields;
            }
            set
            {
                m_strFields = value;
            }
        }
    }
}

最后，不会忘记在要显示属性的相应代码里加上这句吧。propertyGrid.SelectedObject = new AtbRuleProps();

对于PropertyGrid这个控件，我还有很多没弄明白的，以后有空和大家共同学习！