共用方式為

IFeatureSupport.IsPresent 方法

  • 參考

定義

命名空間:
System.Windows.Forms
組件:
System.Windows.Forms.dll

決定指定的功能目前在系統上是否可以使用。

多載

IsPresent(Object)

決定指定功能的任何版本目前在系統上是否可以使用。
IsPresent(Object, Version)

決定目前在系統中是否可以使用指定功能的指定或較新的版本。

IsPresent(Object)

決定指定功能的任何版本目前在系統上是否可以使用。

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

參數

feature
Object

要尋找的功能。

傳回

Boolean

如果功能存在，則為 true，否則為 false。

範例

下列範例會 OSFeatureIFeatureSupport 使用 和 查詢的功能 LayeredWindows 實作。 檢查版本是否為 null ，以判斷功能是否存在。 結果會顯示在文字方塊中。 此程式碼假設 textBox1 已建立並置於表單上。

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

另請參閱

適用於

IsPresent(Object, Version)

決定目前在系統中是否可以使用指定功能的指定或較新的版本。

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

參數

feature
Object

要尋找的功能。

minimumVersion
Version

Version，表示所要尋找之功能的最小版本號碼。

傳回

Boolean

如果功能的要求版本存在則為 true，否則為 false。

範例

下列範例會 OSFeatureIFeatureSupport 使用 和 查詢的功能 LayeredWindows 實作。 檢查版本是否為 null ，以判斷功能是否存在。 結果會顯示在文字方塊中。 此程式碼假設 textBox1 已建立並置於表單上。

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

另請參閱

適用於