Public ReadOnly Property ServiceDataType As String

public string ServiceDataType {get;}

private void ArcGISImageServiceLayer_Initialized(object sender, System.EventArgs e)
{
    // The myArcGISImageServiceLayer (an ArcGISImageServiceLayer object) and TextBlock_ServiceDataType
    // (a TextBlock object) were defined previously in the XAML or code-behind.
                
    // Get the first layer in the LayerInfo collection. 
    ArcGISImageServiceLayer myArcGISImageServiceLayer = (ArcGISDynamicMapServiceLayer)Map1.Layers[0];
    
    // ServiceDataType Property (Read Only).
    TextBlock_ServiceDataType.Text = myArcGISImageServiceLayer.ServiceDataType;
}

Private Sub ArcGISImageServiceLayer_Initialized(ByVal sender As System.Object, ByVal e As System.EventArgs)
    ' The myArcGISImageServiceLayer (an ArcGISImageServiceLayer object) and TextBlock_ServiceDataType
    ' (a TextBlock object) were defined previously in the XAML or code-behind.
    
    ' Get the first layer in the LayerInfo collection. 
    Dim myArcGISImageServiceLayer As ArcGISImageServiceLayer = Map1.Layers.Item(0)
    
    ' ServiceDataType Property (Read Only).
    TextBlock_ServiceDataType.Text = myArcGISImageServiceLayer.ServiceDataType
End Sub