What can be my if statement?

Question

using System;

using System.Collections.Generic;

using System.Linq;

using System.Web;

using System.Web.UI;

using System.Web.UI.WebControls;

public partial class _Default : System.Web.UI.Page

{

protected void Page_Load(object sender, EventArgs e)

{

}

private bool IsFilled()

{

if (TextBox1.Text == "" || TextBox2.Text == "" || TextBox3.Text == "")

{

if (TextBox1.Text == "")

{

Label1.Visible = true;

}

else

Label1.Visible = false;

{

}

if (TextBox2.Text == "")

{

Label2.Visible = true;

}

else

Label2.Visible = false;

{

}

if (TextBox3.Text == "")

{

Label3.Visible = true;

}

else

Label3.Visible = false;

{

}

return true;

}

else

{

Label1.Visible = false;

Label2.Visible = false;

Label3.Visible = false;

return false;

}

}

protected void Button1_Click(object sender, EventArgs e)

{

if (IsFilled())

{

//what can be my if statement?

}

else

{

//what can be my else statement?

//like im going to state here that its already successful? 

}

}

}