c#动态设置combobox控件下拉项宽度以实现下拉项文字可以完全显示。

c#动态设置combobox控件下拉项宽度以实现下拉项文字可以完全显示。

这个几乎是来自这里的啊：
http://blog.csdn.net/ccy3253/archive/2008/01/26/2067304.aspx


0.控件类

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Text;
using System.Windows.Forms;

namespace WindowsApplication1
{
  public partial class CtrlComboBox :ComboBox
  {
    protected override void OnDropDown(EventArgs e)
         {
            base.OnDropDown(e);
            AdjustComboBoxDropDownListWidth();  //调整comboBox的下拉列表的大小
        }

        private void AdjustComboBoxDropDownListWidth()
         {
            Graphics g = null;
            Font font = null;
            try
             {
                int width = this.Width;
                g = this.CreateGraphics();
                font = this.Font;

                //checks if a scrollbar will be displayed.
                //If yes, then get its width to adjust the size of the drop down list.
                int vertScrollBarWidth =
                    (this.Items.Count > this.MaxDropDownItems)
                    ? SystemInformation.VerticalScrollBarWidth : 0;

                int newWidth;
                foreach (object s in this.Items)  //Loop through list items and check size of each items.
                 {
                    if (s != null)
                     {
                        //newWidth = (int)g.MeasureString(s.ToString().Trim(), font).Width
                       newWidth = (int)g.MeasureString(((ComboBoxData)s).StrText, font).Width
                            + vertScrollBarWidth;
                        if (width < newWidth)
                            width = newWidth;   //set the width of the drop down list to the width of the largest item.
                    }
                }
                this.DropDownWidth = width;
            }
            catch
             { }
            finally
             {
                if (g != null)
                    g.Dispose();
            }
        }
  }
}




1.数据源类
public class ComboBoxData
  {
    private string _StrValue;
    private string _StrText;

    public ComboBoxData(string StrValue, String StrText)
    {
      _StrText = StrText;
      _StrValue = StrValue;

    }

    public string StrValue
    {
      get
      {
        return _StrValue;
      }
      set
      {
        _StrValue = value;
      }
    }

    public string StrText
    {
      get
      {
        return _StrText;
      }
      set
      {
        _StrText = value;
      }
    }


  }

2.form 里使用它。



ArrayList al = new ArrayList();
      for (int i = 0; i < 9; i++)
      {
        al.Add( new ComboBoxData("aaaaaaaaaaaaaaaaaaa" + i.ToString(), "aaaaaaaaaaaaaaaaaaa" + i.ToString()));
      }
      al.Add(new ComboBoxData("只要在我们向combox添加完所有项后，调用一下，就可以调整comboBox下拉列表的宽度了", "只要在我们向combox添

加完所有项后，调用一下，就可以调整comboBox下拉列表的宽度了"));
      ctrlComboBox1.DropDownStyle = ComboBoxStyle.DropDownList;
      ctrlComboBox1.DisplayMember = "StrText";
      ctrlComboBox1.ValueMember = "StrValue";
      ctrlComboBox1.DataSource = al;



如果想实现在选择了某项后，combobox以提示的方式来查看选择项的完全text,那要加一个toolTip

 private void comboBox1_MouseMove(object sender, System.Windows.Forms.MouseEventArgs e)
    {
      this.toolTip1.SetToolTip(this.comboBox1, this.comboBox1.Text);
    }