c# - Textbox won't update total

Question

I'm trying to display a total in a text box however the variable the text box outputs will only update if the value assigned to it is greater than the last value instead of adding to the last value.

private void PictureBoxWindFarmMouseClick(object sender, MouseEventArgs e)
{
  decimal captot = 0;
  // Read mouse-click position
  int x = e.X;
  int y = e.Y;
  //collects varibles from the form 
  int hei = _heightTrackBar.Value;
  float rad = (_radiusTrackBar.Value)*0.01f ;
  int bla = Convert.ToInt32(_numberOfBladesUpDown.Value);
  Color pol = colorDialog1.Color;
  Color rot = colorDialog2.Color;
  bool clo = _clockwiseCheckBox.Checked;
  decimal cap = _capacityUpDown.Value;
  captot +=  cap;
  // Create wind turbine at this position, uses collected varibles
  WindTurbine turbine = new WindTurbine( hei, rad, bla, clo, pol, rot, cap, x, y);
  // Add wind turbine to farm list
  _turbines.Add(turbine);
  // Force redraw of the picture box to show changes
  _pictureBoxWindFarm.Refresh();
  _statusLabel.ResetText();
  _statusLabel.Text = ("these"+ _turbines.Count + "wind turbines can generate a total of" + captot + "MW of power.");
}

textbox at lower left

textbox not adding

updates if value is greater

question from:https://stackoverflow.com/questions/65648758/textbox-wont-update-total

Answer 1

GI1 was right the variable just needed to be declared outside the event