FeatureSupport.IsPresent Method (Object)

 

Determines whether any version of the specified feature is installed in the system.

Namespace:   System.Windows.Forms
Assembly:  System.Windows.Forms (in System.Windows.Forms.dll)

Public Overridable Function IsPresent (
	feature As Object
) As Boolean

Parameters

feature
Type: System.Object

The feature to look for.

Return Value

Type: System.Boolean

true if the feature is present; otherwise, false.

Notes to Inheritors:

When you inherit from FeatureSupport, you must override the GetVersionPresent method. When you override this method, check that the class that you use for the feature parameter is the same as the class used for this parameter in the IsPresent method. If the two feature parameters differ, you must also override IsPresent.

The following code example uses the OSFeature implementation of FeatureSupport and queries for the LayeredWindows feature. The version is checked to see if it is null, to determine whether the feature is present. The result is displayed in a text box. This code requires that textBox1 has been created and placed on a form.

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

.NET Framework
Available since 1.1
Return to top
Show: