Server-Side UI Automation Provider - WinForm Sample
2014-09-14
目录
引用程序集
提供程序接口
公开服务器端 UI 自动化提供程序
从 UI 自动化提供程序返回属性
从 UI 自动化提供程序中引发事件
在 UI 自动化提供程序中支持控件模式
WinForm Sample
参考
引用程序集[1]
UI 自动化提供程序项目必须引用以下程序集：
- UIAutomationProviders.dll
- UIAutomationTypes.dll
- WindowsBase.dll
提供程序接口[1]
每个 UI 自动化提供程序必须实现下列接口之一。
|
接口 |
说明 |
|---|---|
|
提供窗口中承载的简单控件的功能，包括对控件模式和属性的支持。 |
|
|
继承自 IRawElementProviderSimple。 为复杂控件中的元素添加功能，包括在片段中导航、设置焦点和返回元素的边框。 |
|
|
继承自 IRawElementProviderFragment。 为复杂控件中的根元素添加功能，包括将子元素定位于指定坐标以及设置整个控件的焦点状态。 |
IRawElementProviderSimple的metadata见图1
图1 metadata - IRawElementProviderSimple
公开服务器端 UI 自动化提供程序[2]
重写窗口过程以捕获 WM_GETOBJECT，以响应客户端应用程序发送到控件窗口的 WM_GETOBJECT 消息时，返回实现 IRawElementProviderSimple（或派生接口）的对象。
/// <summary>
/// Handles WM_GETOBJECT message; others are passed to base handler.
/// </summary>
/// <param name="m">Windows message.</param>
/// <remarks>
/// This method enables UI Automation to find the control.
/// </remarks>
[PermissionSetAttribute(SecurityAction.Demand, Unrestricted = true)]
protected override void WndProc(ref Message m)
{
const int WM_GETOBJECT = 0x003D; if ((m.Msg == WM_GETOBJECT) && (m.LParam.ToInt32() == AutomationInteropProvider.RootObjectId))
{
m.Result = AutomationInteropProvider.ReturnRawElementProvider(
Handle, m.WParam, m.LParam, (IRawElementProviderSimple)this);
return;
}
base.WndProc(ref m);
}
从 UI 自动化提供程序返回属性[3]
实现接口IRawElementProviderSimple方法GetPropertyValue，使得UI 自动化提供程序将元素的属性返回到客户端应用程序。
对于不显式支持的任意属性，提供程序必须返回 null。这样可以确保 UI 自动化尝试从其他源（如宿主窗口提供程序）获取属性。
/// <summary>
/// Returns property values.
/// </summary>
/// <param name="propId">Property identifier.</param>
/// <returns>Property value.</returns>
object IRawElementProviderSimple.GetPropertyValue(int propId)
{
if (propId == AutomationElementIdentifiers.ClassNameProperty.Id)
{
return "CustomButtonControlClass";
}
else if (propId == AutomationElementIdentifiers.ControlTypeProperty.Id)
{
return ControlType.Button.Id;
}
if (propId == AutomationElementIdentifiers.HelpTextProperty.Id)
{
return "Change the button color and pattern.";
}
if (propId == AutomationElementIdentifiers.IsEnabledProperty.Id)
{
return true;
}
else
{
return null;
}
}
从 UI 自动化提供程序中引发事件[4]
下面的代码在自定义按钮控件的实现中引发了UI自动化事件。该实现使UI自动化客户端应用程序能够模拟按钮单击。
为了避免不必要的处理，示例将检查 ClientsAreListening 以确定是否应该引发事件。
/// <summary>
/// Responds to a button click, regardless of whether it was caused by a mouse or
/// keyboard click or by InvokePattern.Invoke.
/// </summary>
private void OnCustomButtonClicked()
{
// TODO Perform program actions invoked by the control. // Raise an event.
if (AutomationInteropProvider.ClientsAreListening)
{
AutomationEventArgs args = new AutomationEventArgs(InvokePatternIdentifiers.InvokedEvent);
AutomationInteropProvider.RaiseAutomationEvent(InvokePatternIdentifiers.InvokedEvent, this, args);
}
}
在 UI 自动化提供程序中支持控件模式[5]
支持控件模式
1.为该元素支持的控件模式实现相应的接口，例如，为 InvokePattern 实现 IInvokeProvider。
/// <summary>
/// Responds to an InvokePattern.Invoke by simulating a MouseDown event.
/// </summary>
void IInvokeProvider.Invoke()
{
// If the control is not enabled, we're responsible for letting UI Automation know.
// It catches the exception and then throws it to the client.
IRawElementProviderSimple provider = this as IRawElementProviderSimple;
if (false == (bool)provider.GetPropertyValue(AutomationElementIdentifiers.IsEnabledProperty.Id))
{
throw new ElementNotEnabledException();
} // Create arguments for the click event. The parameters aren't used.
MouseEventArgs mouseArgs = new MouseEventArgs(MouseButtons.Left, , , , ); // Simulate a mouse click. We cannot call RespondToClick directly,
// because it is illegal to update the UI from a different thread.
MouseEventHandler handler = CustomButton_MouseDown;
BeginInvoke(handler, new object[] { this, mouseArgs });
}
若invoke实现如下，则用客户端模拟点击操作，只会弹出对话框。
void IInvokeProvider.Invoke(){ MessageBox.Show("invoke Pattern."); }
我们可以用UISpy模拟客户端操作，引发invoke事件：
- 选中CustomControl
- 菜单‘View'->'Control Pattern，选择'Call Method'
见下图2，只弹出了MessageBox，customControl的图形并没有改变
图2 UISpy模拟客户端操作，引发invoke事件
2.返回一个对象，其中包含 IRawElementProviderSimple.GetPatternProvider 实现中的每个控件接口的实现。
/// <summary>
/// Returns the object that supports the specified pattern.
/// </summary>
/// <param name="patternId">ID of the pattern.</param>
/// <returns>Object that implements IInvokeProvider.</returns>
object IRawElementProviderSimple.GetPatternProvider(int patternId)
{
if (patternId == InvokePatternIdentifiers.Pattern.Id)
{
return this;
}
else
{
return null;
}
}
WinForm Sample[6]
using System;
using System.Collections.Generic;
using System.Text;
using System.Windows.Automation.Provider;
using System.Windows.Automation;
using System.Drawing;
using System.Windows.Forms;
using System.Diagnostics;
using System.Security.Permissions; namespace ElementProvider
{
class CustomButton : Control, IRawElementProviderSimple, IInvokeProvider
{
bool buttonState = false;
IntPtr myHandle; /// <summary>
/// Constructor.
/// </summary>
/// <param name="rect">Position and size of control.</param>
public CustomButton()
{
myHandle = Handle; // Add event handlers.
MouseDown += new System.Windows.Forms.MouseEventHandler(this.CustomButton_MouseDown);
this.KeyPress += new System.Windows.Forms.KeyPressEventHandler(this.CustomButton_KeyPress);
this.GotFocus += new EventHandler(CustomButton_ChangeFocus);
this.LostFocus += new EventHandler(CustomButton_ChangeFocus);
} /// <summary>
/// Handles WM_GETOBJECT message; others are passed to base handler.
/// </summary>
/// <param name="m">Windows message.</param>
/// <remarks>
/// This method enables UI Automation to find the control.
/// </remarks>
[PermissionSetAttribute(SecurityAction.Demand, Unrestricted = true)]
protected override void WndProc(ref Message m)
{
const int WM_GETOBJECT = 0x003D; if ((m.Msg == WM_GETOBJECT) && (m.LParam.ToInt32() == AutomationInteropProvider.RootObjectId))
{
m.Result = AutomationInteropProvider.ReturnRawElementProvider(
Handle, m.WParam, m.LParam, (IRawElementProviderSimple)this);
return;
}
base.WndProc(ref m);
} /// <summary>
/// Ensure that the focus rectangle is drawn or erased when focus changes.
/// </summary>
/// <param name="sender"></param>
/// <param name="e"></param>
void CustomButton_ChangeFocus(object sender, EventArgs e)
{
Refresh();
} /// <summary>
/// Handles Paint event.
/// </summary>
/// <param name="e">Event arguments.</param>
protected override void OnPaint(PaintEventArgs e)
{
Rectangle buttonRect = new Rectangle(ClientRectangle.Left + ,
ClientRectangle.Top + ,
ClientRectangle.Width - ,
ClientRectangle.Height - );
System.Drawing.Drawing2D.HatchBrush brush;
if (buttonState)
{
brush = new System.Drawing.Drawing2D.HatchBrush(
System.Drawing.Drawing2D.HatchStyle.DarkHorizontal, Color.Red, Color.White);
}
else
{
brush = new System.Drawing.Drawing2D.HatchBrush(
System.Drawing.Drawing2D.HatchStyle.DarkVertical, Color.Green, Color.White);
} e.Graphics.FillRectangle(brush, buttonRect);
if (Focused)
{
ControlPaint.DrawFocusRectangle(e.Graphics, ClientRectangle);
}
} /// <summary>
/// Responds to a button click, regardless of whether it was caused by a mouse or
/// keyboard click or by InvokePattern.Invoke.
/// </summary>
private void RespondToClick()
{
buttonState = !buttonState;
this.Focus();
this.Refresh(); // Raise an event.
if (AutomationInteropProvider.ClientsAreListening)
{
AutomationEventArgs args = new AutomationEventArgs(InvokePatternIdentifiers.InvokedEvent);
AutomationInteropProvider.RaiseAutomationEvent(InvokePatternIdentifiers.InvokedEvent, this, args);
}
} /// <summary>
/// Handles MouseDown event.
/// </summary>
/// <param name="sender">Object that raised the event.</param>
/// <param name="e">Event arguments.</param>
public void CustomButton_MouseDown(object sender, MouseEventArgs e)
{
RespondToClick();
} /// <summary>
/// Handles Keypress event.
/// </summary>
/// <param name="sender">Object that raised the event.</param>
/// <param name="e">Event arguments.</param>
public void CustomButton_KeyPress(object sender, KeyPressEventArgs e)
{
if (e.KeyChar == (char)Keys.Space)
{
RespondToClick();
}
} #region IRawElementProviderSimple /// <summary>
/// Returns the object that supports the specified pattern.
/// </summary>
/// <param name="patternId">ID of the pattern.</param>
/// <returns>Object that implements IInvokeProvider.</returns>
object IRawElementProviderSimple.GetPatternProvider(int patternId)
{
if (patternId == InvokePatternIdentifiers.Pattern.Id)
{
return this;
}
else
{
return null;
}
} /// <summary>
/// Returns property values.
/// </summary>
/// <param name="propId">Property identifier.</param>
/// <returns>Property value.</returns>
object IRawElementProviderSimple.GetPropertyValue(int propId)
{
if (propId == AutomationElementIdentifiers.ClassNameProperty.Id)
{
return "CustomButtonControlClass";
}
else if (propId == AutomationElementIdentifiers.ControlTypeProperty.Id)
{
return ControlType.Button.Id;
}
if (propId == AutomationElementIdentifiers.HelpTextProperty.Id)
{
return "Change the button color and pattern.";
}
if (propId == AutomationElementIdentifiers.IsEnabledProperty.Id)
{
return true;
}
else
{
return null;
}
} /// <summary>
/// Tells UI Automation that this control is hosted in an HWND, which has its own
/// provider.
/// </summary>
IRawElementProviderSimple IRawElementProviderSimple.HostRawElementProvider
{
get
{
return AutomationInteropProvider.HostProviderFromHandle(myHandle);
}
} /// <summary>
/// Retrieves provider options.
/// </summary>
ProviderOptions IRawElementProviderSimple.ProviderOptions
{
get
{
return ProviderOptions.ServerSideProvider;
}
}
#endregion IRawElementProviderSimple #region IInvokeProvider /// <summary>
/// Responds to an InvokePattern.Invoke by simulating a MouseDown event.
/// </summary>
void IInvokeProvider.Invoke()
{
// If the control is not enabled, we're responsible for letting UI Automation know.
// It catches the exception and then throws it to the client.
IRawElementProviderSimple provider = this as IRawElementProviderSimple;
if (false == (bool)provider.GetPropertyValue(AutomationElementIdentifiers.IsEnabledProperty.Id))
{
throw new ElementNotEnabledException();
} // Create arguments for the click event. The parameters aren't used.
MouseEventArgs mouseArgs = new MouseEventArgs(MouseButtons.Left, , , , ); // Simulate a mouse click. We cannot call RespondToClick directly,
// because it is illegal to update the UI from a different thread.
MouseEventHandler handler = CustomButton_MouseDown;
BeginInvoke(handler, new object[] { this, mouseArgs });
} #endregion InvokeProvider } // CustomButton class.
} // Namespace.
图3 UISpy Co年trol view
参考
[3] 从 UI 自动化提供程序返回属性