create tank in form c#

Hi all

I create a Tank control  in my Window Form but de Fill Area donsn't  reflect the Value of de Tank, Can Any body Helpme please ?

private void Form1_Load(object sender, EventArgs e)
{
NationalInstruments.UI.WindowsForms.Tank bat1 = new NationalInstruments.UI.WindowsForms.Tank();
((System.ComponentModel.ISupportInitialize)(bat1)).BeginInit();
bat1.Name = "bat1";
bat1.Location = new System.Drawing.Point(100, 200);
bat1.Size = new System.Drawing.Size(100, 200);
bat1.ScaleVisible = true;
bat1.Visible = true;

bat1.Range = new Range(0, 20);
bat1.FillColor = Color.Red;
bat1.Value = 30;

bat1.TankStyle = TankStyle.Raised;
bat1.FillMode = NumericFillMode.ToMinimum;
bat1.FillBaseValue = 0;
bat1.FillStyle = FillStyle.Solid;
this.Controls.Add(bat1);
this.Refresh();

}