autoComplete combobox

王朝other·作者佚名  2006-01-09
窄屏简体版  字體: |||超大  

曾经在网上遇到过有人问关于自动填充的ComboBox的问题,当然没有在意,谁知道后来也因为软件开发需要碰到了同样的问题。于是只好到处找资料,谁知道网上的仅仅只能实现自动填充的功能,并不能象IE栏一样,碰到有相同的信息,可以展开ComboBox并高亮选中的内容。( 比容,ComboBox下有3天记录,分别是:eqweq,fasdfs,tyr”当我在输入字符e的时候,应当文本框中显示eqweq并展开下拉框,选中eqweq)。百般无赖,只好对代码进行研究,经过稍稍的改动,已经可以实现我所预想的功能,源代码如下:

using System;

using System.Collections;

using System.ComponentModel;

using System.Drawing;

using System.Data;

using System.Text;

using System.Windows.Forms;

namespace DigitalCult

{

/// <summary>

/// Summary description for ACComboBox.

/// </summary>

public class ACComboBox : System.Windows.Forms.ComboBox

{ private bool autoComplete;

[DefaultValue(true),

Description("Auto-completes text if a match is found in the items collection."),

Category("Behavior")]

public bool AutoComplete

{

get { return autoComplete; }

set { autoComplete = value; }

}

/// <summary>

/// Required designer variable.

/// </summary>

private Container components = null;

/// <summary>

/// Default constructor.

/// </summary>

public ACComboBox()

{

// This call is required by the Windows.Forms Form Designer.

InitializeComponent();

// Add any initialization after the InitComponent call

this.autoComplete = true;

this.KeyPress += new KeyPressEventHandler( this.OnKeyPress );

}

/// <summary>

/// Clean up any resources being used.

/// </summary>

protected override void Dispose( bool disposing )

{

if( disposing )

{

if( components != null )

components.Dispose();

}

base.Dispose( disposing );

}

private void OnKeyPress( object sender, KeyPressEventArgs e )

{

if ( autoComplete )

{

ACComboBox acComboBox = (ACComboBox)sender;

if ( !e.KeyChar.Equals( (char)8 ) )

{

SearchItems( acComboBox, ref e );

}

else

e.Handled = false;

}

else

e.Handled = false;

}

/// <summary>

/// Searches the combo box item list for a match and selects it.

/// If no match is found, then selected index defaults to -1.

/// </summary>

///

///

private void SearchItems( ACComboBox acComboBox, ref KeyPressEventArgs e )

{

int selectionStart = acComboBox.SelectionStart;

int selectionLength = acComboBox.SelectionLength;

int selectionEnd = selectionStart + selectionLength;

int index;

StringBuilder sb = new StringBuilder();

sb.Append( acComboBox.Text.Substring( 0, selectionStart ) )

.Append( e.KeyChar.ToString() )

.Append( acComboBox.Text.Substring( selectionEnd ) );

index = acComboBox.FindString( sb.ToString() );

if ( index == -1 )

e.Handled = false;

else

{

acComboBox.SelectedIndex = index;

acComboBox.Select( selectionStart+1, acComboBox.Text.Length-(selectionStart+1) );

e.Handled = true;

}

}

#region Component Designer generated code

/// <summary>

/// Required method for Designer support - do not modify

/// the contents of this method with the code editor.

/// </summary>

private void InitializeComponent()

{

components = new System.ComponentModel.Container();

}

#endregion

}

}

具体使用方法如下:

1、在你程序中添加新的组件类。

2、把上面的代码的命名空间(namespace )改成你程序的命名空间

3、找到你需要它具备自动功能的ComboBox。比如comboBox1

private System.Windows.Forms.ComboBox comboBox1;

改成private ACComboBox comboBox1;( ACComboBox为你写的控件的类名)

然后在窗体自动生成的代码中找到初始化的语句

this.comboBox1 = new System.Windows.Forms.ComboBox();

改成this.comboBox1 = new ACComboBox ();

OK,现在你的ComboBox已经具有自动功能了。

 
 
 
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