[Klezard]插入符组件(Caret)第二版

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

在有些时候,我们需要在自己的控件中加入象TextBox一样的插入符

这个功能我没有使用上一版所用的Caret API

而直接用了BitBlt函数完成

using System;

using System.Drawing;

using System.Windows.Forms;

using System.Runtime.InteropServices;

namespace Klezard.Windows.Forms

{

/// <summary>

/// 插入符

/// </summary>

public sealed class Caret : System.ComponentModel.Component

{

#region Native

private Timer tim = new Timer();

private const string User32 = "User32.dll";

private const string Gdi32 = "Gdi32.dll";

private static int DSTINVERT = 0x550009;

[DllImport(Gdi32)]

private static extern int BitBlt(

IntPtr hDestDC, int x, int y, int nWidth, int nHeight,

IntPtr hSrcDC, int xSrc, int ySrc, int dwRop);

[DllImport(User32)]

private static extern IntPtr GetWindowDC(IntPtr hWnd);

[DllImport(User32)]

private static extern IntPtr GetDC(IntPtr hWnd);

[DllImport(User32)]

private static extern int ReleaseDC(IntPtr hWnd, IntPtr hdc);

#endregion

private IntPtr dc;

private Control _HostControl;

private Caret() { }

Point _Position = Point.Empty;

Size _Size;

/// <summary>

/// 创建一个插入符

/// </summary>

/// <param name="ctl">插入符宿主</param>

/// <remarks>创建完成后插入符默认为隐藏的</remarks>

public Caret(Control ctl):this(ctl,8,16) { }

/// <summary>

/// 使用特定的大小创建一个插入符

/// </summary>

/// <param name="ctl">宿主</param>

/// <param name="width">宽度</param>

/// <param name="height">高度</param>

/// <remarks>创建完成后插入符默认为隐藏的</remarks>

public Caret(Control ctl, int width, int height)

{

if (ctl == null)

throw new NullReferenceException();

_HostControl = ctl;

dc = GetDC(ctl.Handle);

if (dc == IntPtr.Zero)

throw new NullReferenceException();

_Size = new Size(width, height);

tim.Interval = 530;

tim.Tick += new EventHandler(tim_Tick);

}

/// <summary>

/// 释放该插入符对象

/// </summary>

public void Destroy()

{

if (_HostControl != null)

ReleaseDC(_HostControl.Handle, dc);

this.Dispose();

}

/// <summary>

/// 显示插入符

/// </summary>

public void Show() { tim.Start(); }

/// <summary>

/// 隐藏插入符,隐藏效果会叠加,即调用了几次Hide,要再次显示时就要调用几次Show

/// </summary>

public void Hide() { tim.Stop(); }

//// <summary>

/// 宿主窗体

/// </summary>

public Control HostControl { get { return _HostControl; } }

//// <summary>

/// 获得或设置所有插入符闪烁时间间隔

/// </summary>

public int BlinkTime

{

get { return tim.Interval; }

set { tim.Interval = value; }

}

//// <summary>

/// 获得或设置插入符的相对位置

/// </summary>

public Point Position

{

get { return _Position; }

set

{

_Position = value;

HostControl.Refresh();

}

}

/// <summary>

/// 获得或设置插入符的大小

/// </summary>

public Size Size

{

get { return _Size; }

set

{

_Size = value;

HostControl.Refresh();

}

}

void tim_Tick(object sender, EventArgs e)

{

BitBlt(dc, Position.X, Position.Y, Size.Width, Size.Height, IntPtr.Zero, 0, 0, DSTINVERT);

}

}

}

转载请注明出处,如果您要使用该代码,请告之作者

 
 
 
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