IFeatureSupport.IsPresent IFeatureSupport.IsPresent IFeatureSupport.IsPresent IFeatureSupport.IsPresent Method

定义

确定指定的功能在系统中当前是否可用。Determines whether the specified feature is currently available on the system.

重载

IsPresent(Object) IsPresent(Object) IsPresent(Object) IsPresent(Object)

确定系统当前是否有指定功能的任意版本。Determines whether any version of the specified feature is currently available on the system.

IsPresent(Object, Version) IsPresent(Object, Version) IsPresent(Object, Version) IsPresent(Object, Version)

确定系统当前是否有指定功能的指定版本或更新版本。Determines whether the specified or newer version of the specified feature is currently available on the system.

IsPresent(Object) IsPresent(Object) IsPresent(Object) IsPresent(Object)

确定系统当前是否有指定功能的任意版本。Determines whether any version of the specified feature is currently available on the system.

public:
 bool IsPresent(System::Object ^ feature);
public bool IsPresent (object feature);
abstract member IsPresent : obj -> bool
Public Function IsPresent (feature As Object) As Boolean

参数

feature
Object Object Object Object

要查找的功能。The feature to look for.

返回

如果提供该功能,则为 true;否则为 falsetrue if the feature is present; otherwise, false.

示例

下面的示例使用OSFeature IFeatureSupport和查询来实现该LayeredWindows功能。The following example uses the OSFeature implementation of IFeatureSupport and queries for the LayeredWindows feature. 检查版本是否为null, 以确定该功能是否存在。The version is checked to see if it is null, to determine whether the feature is present. 结果将显示在文本框中。The result is displayed in a text box. 此代码假定textBox1已创建并放置在窗体上。This code assumes textBox1 has been created and placed on a form.

private:
   void LayeredWindows()
   {
      // Gets the version of the layered windows feature.
      Version^ myVersion = OSFeature::Feature->GetVersionPresent(
         OSFeature::LayeredWindows );
      
      // Prints whether the feature is available.
      if ( myVersion != nullptr )
      {
         textBox1->Text = "Layered windows feature is installed.\n";
      }
      else
      {
         textBox1->Text = "Layered windows feature is not installed.\n";
      }

      
      // This is an alternate way to check whether a feature is present.
      if ( OSFeature::Feature->IsPresent( OSFeature::LayeredWindows ) )
      {
         textBox1->Text = String::Concat( textBox1->Text,
            "Again, layered windows feature is installed." );
      }
      else
      {
         textBox1->Text = String::Concat( textBox1->Text,
            "Again, layered windows feature is not installed." );
      }
   }
private void LayeredWindows() {
   // Gets the version of the layered windows feature.
   Version myVersion = OSFeature.Feature.GetVersionPresent(OSFeature.LayeredWindows);

   // Prints whether the feature is available.
   if (myVersion != null)
      textBox1.Text = "Layered windows feature is installed." + '\n';
   else
      textBox1.Text = "Layered windows feature is not installed." + '\n';

   // This is an alternate way to check whether a feature is present.
   if (OSFeature.Feature.IsPresent(OSFeature.LayeredWindows))
      textBox1.Text += "Again, layered windows feature is installed.";
   else
      textBox1.Text += "Again, layered windows feature is not installed.";
}

Private Sub LayeredWindows()
    ' Gets the version of the layered windows feature.
    Dim myVersion As Version = _
       OSFeature.Feature.GetVersionPresent(OSFeature.LayeredWindows)
       
    ' Prints whether the feature is available.
    If (myVersion IsNot Nothing) Then
        textBox1.Text = "Layered windows feature is installed." & _
           ControlChars.CrLf
    Else
        textBox1.Text = "Layered windows feature is not installed." & _
           ControlChars.CrLf
    End If 
    'This is an alternate way to check whether a feature is present.
    If OSFeature.Feature.IsPresent(OSFeature.LayeredWindows) Then
        textBox1.Text &= "Again, layered windows feature is installed."
    Else
        textBox1.Text &= "Again, layered windows feature is not installed."
    End If
End Sub

另请参阅

IsPresent(Object, Version) IsPresent(Object, Version) IsPresent(Object, Version) IsPresent(Object, Version)

确定系统当前是否有指定功能的指定版本或更新版本。Determines whether the specified or newer version of the specified feature is currently available on the system.

public:
 bool IsPresent(System::Object ^ feature, Version ^ minimumVersion);
public bool IsPresent (object feature, Version minimumVersion);
abstract member IsPresent : obj * Version -> bool
Public Function IsPresent (feature As Object, minimumVersion As Version) As Boolean

参数

feature
Object Object Object Object

要查找的功能。The feature to look for.

minimumVersion
Version Version Version Version

Version 表示要查找功能的最小版本号。A Version representing the minimum version number of the feature to look for.

返回

如果有所请求的该功能版本,值为 true;反之,值为 falsetrue if the requested version of the feature is present; otherwise, false.

示例

下面的示例使用OSFeature IFeatureSupport和查询来实现该LayeredWindows功能。The following example uses the OSFeature implementation of IFeatureSupport and queries for the LayeredWindows feature. 检查版本是否为null, 以确定该功能是否存在。The version is checked to see if it is null, to determine whether the feature is present. 结果将显示在文本框中。The result is displayed in a text box. 此代码假定textBox1已创建并放置在窗体上。This code assumes textBox1 has been created and placed on a form.

private:
   void LayeredWindows()
   {
      // Gets the version of the layered windows feature.
      Version^ myVersion = OSFeature::Feature->GetVersionPresent(
         OSFeature::LayeredWindows );
      
      // Prints whether the feature is available.
      if ( myVersion != nullptr )
      {
         textBox1->Text = "Layered windows feature is installed.\n";
      }
      else
      {
         textBox1->Text = "Layered windows feature is not installed.\n";
      }

      
      // This is an alternate way to check whether a feature is present.
      if ( OSFeature::Feature->IsPresent( OSFeature::LayeredWindows ) )
      {
         textBox1->Text = String::Concat( textBox1->Text,
            "Again, layered windows feature is installed." );
      }
      else
      {
         textBox1->Text = String::Concat( textBox1->Text,
            "Again, layered windows feature is not installed." );
      }
   }
private void LayeredWindows() {
   // Gets the version of the layered windows feature.
   Version myVersion = OSFeature.Feature.GetVersionPresent(OSFeature.LayeredWindows);

   // Prints whether the feature is available.
   if (myVersion != null)
      textBox1.Text = "Layered windows feature is installed." + '\n';
   else
      textBox1.Text = "Layered windows feature is not installed." + '\n';

   // This is an alternate way to check whether a feature is present.
   if (OSFeature.Feature.IsPresent(OSFeature.LayeredWindows))
      textBox1.Text += "Again, layered windows feature is installed.";
   else
      textBox1.Text += "Again, layered windows feature is not installed.";
}

Private Sub LayeredWindows()
    ' Gets the version of the layered windows feature.
    Dim myVersion As Version = _
       OSFeature.Feature.GetVersionPresent(OSFeature.LayeredWindows)
       
    ' Prints whether the feature is available.
    If (myVersion IsNot Nothing) Then
        textBox1.Text = "Layered windows feature is installed." & _
           ControlChars.CrLf
    Else
        textBox1.Text = "Layered windows feature is not installed." & _
           ControlChars.CrLf
    End If 
    'This is an alternate way to check whether a feature is present.
    If OSFeature.Feature.IsPresent(OSFeature.LayeredWindows) Then
        textBox1.Text &= "Again, layered windows feature is installed."
    Else
        textBox1.Text &= "Again, layered windows feature is not installed."
    End If
End Sub

另请参阅

适用于