QueryAccessibilityHelpEventArgs 类


QueryAccessibilityHelp 事件提供数据。Provides data for the QueryAccessibilityHelp event.

public ref class QueryAccessibilityHelpEventArgs : EventArgs
public class QueryAccessibilityHelpEventArgs : EventArgs
type QueryAccessibilityHelpEventArgs = class
    inherit EventArgs
Public Class QueryAccessibilityHelpEventArgs
Inherits EventArgs


下面的代码示例演示如何创建可访问感知的图表控件, AccessibleObject并使用和Control.ControlAccessibleObject类公开可访问的信息。The following code example demonstrates the creation of an accessibility-aware chart control, using the AccessibleObject and Control.ControlAccessibleObject classes to expose accessible information. 控件将两条曲线与图例一起绘制。The control plots two curves along with a legend. CreateAccessibilityInstanceChartControlAccessibleObject 派生的类在方法中用于为图表控件提供自定义的可访问信息。ControlAccessibleObjectThe ChartControlAccessibleObject class, which derives from ControlAccessibleObject, is used in the CreateAccessibilityInstance method to provide custom accessible information for the chart control. 因为图表图例不是实际Control的控件, 而是由图表控件绘制的, 所以它不是任何内置的可访问信息。Because the chart legend is not an actual Control-based control, but instead is drawn by the chart control, it does not any built-in accessible information. 因此, ChartControlAccessibleObjectCurveLegendAccessibleObjectGetChild重写方法以返回, 该方法表示图例的每个部分的可访问信息。Because of this, the ChartControlAccessibleObject class overrides the GetChild method to return the CurveLegendAccessibleObject that represents accessible information for each part of the legend. 当可访问感知的应用程序使用此控件时, 控件可以提供必需的可访问信息。When an accessible-aware application uses this control, the control can provide the necessary accessible information.

此示例演示如何将QueryAccessibilityHelpEventArgsQueryAccessibilityHelp与事件一起使用。This example demonstrates using the QueryAccessibilityHelpEventArgs class with the QueryAccessibilityHelp event. 有关完整的代码示例, 请参阅类概述。AccessibleObjectSee the AccessibleObject class overview for the complete code example.

// Handles the QueryAccessibilityHelp event.
void ChartControl_QueryAccessibilityHelp( Object^ /*sender*/, System::Windows::Forms::QueryAccessibilityHelpEventArgs^ e )
   e->HelpString = "Displays chart data";
// Handles the QueryAccessibilityHelp event.
private void ChartControl_QueryAccessibilityHelp(object sender, 
                            System.Windows.Forms.QueryAccessibilityHelpEventArgs e)
    e.HelpString = "Displays chart data";
' Handle the QueryAccessibilityHelp event.
Private Sub ChartControl_QueryAccessibilityHelp(sender As Object, _
                   e As System.Windows.Forms.QueryAccessibilityHelpEventArgs) Handles MyBase.QueryAccessibilityHelp
    e.HelpString = "Displays chart data"
End Sub 


类公开公共QueryAccessibilityHelp事件。 ControlThe Control class exposes a public QueryAccessibilityHelp event. 您可以使用QueryAccessibilityHelpEventArgs类的属性将特定控件的自定义帮助返回到可访问的客户端, 如屏幕阅读器。You can use the properties of the QueryAccessibilityHelpEventArgs class to return custom help for a particular control to an accessible client, such as a screen reader. 处理QueryAccessibilityHelp事件时, 必须将HelpNamespaceHelpKeywordHelpString属性的值设置为相应的值。When you handle the QueryAccessibilityHelp event, you must set the values of the HelpNamespace, HelpKeyword, and HelpString properties to appropriate values.


HelpKeyword属性应为数字帮助主题 ID 的字符串表示形式。The HelpKeyword property should be a string representation of a numeric Help topic ID.



初始化 QueryAccessibilityHelpEventArgs 类的新实例。Initializes a new instance of the QueryAccessibilityHelpEventArgs class.

QueryAccessibilityHelpEventArgs(String, String, String)

初始化 QueryAccessibilityHelpEventArgs 类的新实例。Initializes a new instance of the QueryAccessibilityHelpEventArgs class.



获取或设置用于指定控件的帮助关键字。Gets or sets the Help keyword for the specified control.


获取或设置指定帮助文件的名称的值。Gets or sets a value specifying the name of the Help file.


获取或设置定义要为 AccessibleObject 获取何种帮助的字符串。Gets or sets the string defining what Help to get for the AccessibleObject.



确定指定的对象是否等于当前对象。Determines whether the specified object is equal to the current object.

(继承自 Object)

用作默认哈希函数。Serves as the default hash function.

(继承自 Object)

获取当前实例的 TypeGets the Type of the current instance.

(继承自 Object)

创建当前 Object 的浅表副本。Creates a shallow copy of the current Object.

(继承自 Object)

返回一个表示当前对象的 string。Returns a string that represents the current object.

(继承自 Object)