SelectionPattern.SelectionPatternInformation.IsSelectionRequired 屬性

定義

命名空間:

System.Windows.Automation

組件:

UIAutomationClient.dll

取得值，指定容器是否需要至少選取一個子項目。

public:
 property bool IsSelectionRequired { bool get(); };

public bool IsSelectionRequired { get; }

member this.IsSelectionRequired : bool

Public ReadOnly Property IsSelectionRequired As Boolean

屬性值

Boolean

如果控制項需要至少選取一個項目，則為 true；否則為 false。

範例

在下列範例中， SelectionPattern 會從 AutomationElement 取得控制項模式，然後用來擷取屬性值。

///--------------------------------------------------------------------
/// <summary>
/// Obtains a SelectionPattern control pattern from an 
/// automation element.
/// </summary>
/// <param name="targetControl">
/// The automation element of interest.
/// </param>
/// <returns>
/// A SelectionPattern object.
/// </returns>
///--------------------------------------------------------------------
private SelectionPattern GetSelectionPattern(
    AutomationElement targetControl)
{
    SelectionPattern selectionPattern = null;

    try
    {
        selectionPattern =
            targetControl.GetCurrentPattern(SelectionPattern.Pattern)
            as SelectionPattern;
    }
    // Object doesn't support the SelectionPattern control pattern
    catch (InvalidOperationException)
    {
        return null;
    }

    return selectionPattern;
}

'''--------------------------------------------------------------------
''' <summary>
''' Obtains a SelectionPattern control pattern from an 
''' automation element.
''' </summary>
''' <param name="targetControl">
''' The automation element of interest.
''' </param>
''' <returns>
''' A SelectionPattern object.
''' </returns>
'''--------------------------------------------------------------------
Private Function GetSelectionPattern( _
ByVal targetControl As AutomationElement) As SelectionPattern
    Dim selectionPattern As SelectionPattern = Nothing

    Try
        selectionPattern = DirectCast( _
        targetControl.GetCurrentPattern(selectionPattern.Pattern), _
        SelectionPattern)
    ' Object doesn't support the SelectionPattern control pattern
    Catch
        Return Nothing
    End Try

    Return selectionPattern
End Function 'GetSelectionPattern

///--------------------------------------------------------------------
/// <summary>
/// Gets the current property values from target.
/// </summary>
/// <param name="selectionPattern">
/// A SelectionPattern control pattern obtained from 
/// an automation element representing the selection control.
/// </param>
/// <param name="automationProperty">
/// The automation property of interest.
/// </param>
///--------------------------------------------------------------------
private bool GetSelectionObjectProperty(
    SelectionPattern selectionPattern,
    AutomationProperty automationProperty)
{
    if (automationProperty.Id == 
        SelectionPattern.CanSelectMultipleProperty.Id)
    {
        return selectionPattern.Current.CanSelectMultiple;
    }
    if (automationProperty.Id == 
        SelectionPattern.IsSelectionRequiredProperty.Id)
    {
        return selectionPattern.Current.IsSelectionRequired;
    }
    return false;
}

'''--------------------------------------------------------------------
''' <summary>
''' Gets the current property values from target.
''' </summary>
''' <param name="selectionPattern">
''' A SelectionPattern control pattern obtained from 
''' an automation element representing the selection control.
''' </param>
''' <param name="automationProperty">
''' The automation property of interest.
''' </param>
'''--------------------------------------------------------------------
Private Function GetSelectionObjectProperty( _
ByVal selectionPattern As SelectionPattern, _
ByVal automationProperty As AutomationProperty) As Boolean
    If automationProperty.Id = _
    selectionPattern.CanSelectMultipleProperty.Id Then
        Return selectionPattern.Current.CanSelectMultiple
    End If
    If automationProperty.Id = _
    selectionPattern.IsSelectionRequiredProperty.Id Then
        Return selectionPattern.Current.IsSelectionRequired
    End If
    Return False
End Function 'GetSelectionObjectProperty

備註

這個屬性可以是動態的。 例如，控制項的最初狀態可能預設沒有選取任何項目，表示 IsSelectionRequired 為 false。 不過，在選取項目之後，控制項就必須至少有一個項目一律保持為選取。