Need to simulate a message box close

}
void Result()
{
   float Value_Extract = 0;
   int Lenght = 0;
    string ValueToBeExtracted;

    //Value_Extract = Convert.ToSingle(rtbIncoming.Text); errors due to the N
    //Length - 1 to get rid of N                     need to change
   // MessageBox.Show(rtbIncoming.Text);
    Thread.Sleep(1500);
    MessageBox.Show(rtbIncoming.Text);
    Lenght = ((rtbIncoming.TextLength)-3);
    ValueToBeExtracted = rtbIncoming.Text.Substring(1,Lenght-2);

   // MessageBox.Show(ValueToBeExtracted);

    float.TryParse(ValueToBeExtracted,out  Value_Extract);

  //  MessageBox.Show(Convert.ToString(Value_Extract));
    if (Value_Extract < 0.45)
    {

        MessageBox.Show("Too Low", "", MessageBoxButtons.OK, MessageBoxIcon.Error);
    }
    else if (Value_Extract > 0.55)
    {

        MessageBox.Show("Too High", "", MessageBoxButtons.OK, MessageBoxIcon.Error);
    }
    else
    {
       //txtResult.Text = Value_Extract.ToString();
        MessageBox.Show("Pass", "", MessageBoxButtons.OK, MessageBoxIcon.Information);
    }

var sw = new StopWatch();
var maxTime = TimeSpan.FromMinutes(5);
sw.Start();
for (int i=0; i < 100; i++)
{  
    RunfunctionA();

    if(sw.Elapsed <= maxTime)
    {
        RunfunctionB();
        break;
    }
}