Public ReadOnly Property IsValid As Boolean

Dim instance As Page
Dim value As Boolean

value = instance.IsValid

public bool IsValid { get; }

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

/** @property */
public boolean get_IsValid ()

public function get IsValid () : boolean

Sub ValidateBtn_Click(sender As Object, e As EventArgs)

   If (Page.IsValid) Then
      lblOutput.Text = "Page is Valid!"
   Else
      lblOutput.Text = "Some of the required fields are empty."
   End If

End Sub

 void ValidateBtn_Click(Object Sender, EventArgs E) {

    if (Page.IsValid == true) {
       lblOutput.Text = "Page is Valid!";
    }
    else {
       lblOutput.Text = "Some of the required fields are empty.";
    } 
}

 function ValidateBtn_Click(Sender, e : EventArgs) {

    if (Page.IsValid == true) {
       lblOutput.Text = "Page is Valid!";
    }
    else {
       lblOutput.Text = "Some of the required fields are empty";
    } 
}