title: Creating Rectangle in PictureBox using PictureBox.CreateGraphics
body: <p>in code below in button click function i want to create a rectangle in the picureBox but when I execute it for first time it draws nothing , but for the second time clicking the rectngle appears , why?</p>
  
  <p>the if statement is true in both time.</p>
  
  <pre><code>    private void btnChamber_Click(object sender, EventArgs e)
      {
  
          //pictureBox1.Visible = true;
  
          if (cmbShowResult.SelectedIndex == 0 &amp;&amp; ChamberType.SelectedIndex == 0)
          {
              chart1.Visible = false;
              chart2.Visible = false;
              chart3.Visible = false;
              chart4.Visible = false;
              chart5.Visible = false;
              pictureBox1.Visible = true;
              //pictureBox1.Enabled = true;
              Graphics gg = pictureBox1.CreateGraphics();
  
              //gg.ClipBounds.X = 0;
              //gg.ClipBounds.Y = 0;
              //AddChartStyle(gg);
              chartArea1.X = 0;
              chartArea1.Y = 0;
              chartArea1.Height = 298;
              chartArea1.Width = 450;
  
  
              plotArea.X = 40;
              plotArea.Y = 10;
              plotArea.Height = 258;
              plotArea.Width = 400;
  
  
  
              xLimMin = -(float.Parse(txtWidth.Text)) / 2;
              xLimMax = (float.Parse(txtWidth.Text)) / 2;
              yLimMin = -(float.Parse(txtLeft.Text)) * 3f;
              yLimMax = (float.Parse(txtLeft.Text)) * 3f;
  
              Pen aPen = new Pen(chartBorderColor, 1f);
              SolidBrush aBrush = new SolidBrush(chartBorderColor);
              gg.FillRectangle(aBrush, chartArea1);
              gg.DrawRectangle(aPen, chartArea1);
              aPen = new Pen(plotBorderColor, 1f);
              aBrush = new SolidBrush(plotBackColor);
              gg.FillRectangle(aBrush, plotArea);
  
              gg.DrawRectangle(aPen, plotArea);
              //AddChartStyle(g);
  
              //pictureBox1.Visible = true;
              //gg = pictureBox1.CreateGraphics();
  
  
              //gg.Flush();
              //gg.Save();
              //pictureBox1.Show();
              //pictureBox1.Invalidate();
              //chart6.Visible = true; 
  
          }
          pictureBox1.Visible = true;
          //gg.Flush();
  
      }
  </code></pre>