C#

private unsafe void ApplyAlphaToImage(Bitmap image)
{
   if (image == null || _alpha == 255)
      return;

   int imageWidth = image.Width;
   int imageHeight = image.Height;

   BitmapData data = null;
   try 
   {
      data = image.LockBits(new Rectangle(0, 0, imageWidth, imageHeight), 
         ImageLockMode.ReadWrite, PixelFormat.Format32bppArgb);
      int scan0 = data.Scan0.ToInt32();
      int stride = data.Stride;

      byte * colPixel;

      byte invertedAlpha = (byte)(255 - _alpha);

      byte * rowPixel = (byte *)scan0;
      for (int y = 0; y < imageHeight; y++)
      {
         colPixel = rowPixel + 3;
         for (int x = 0; x < imageWidth; x++)
         {
            if (*(colPixel) < invertedAlpha)
               *(colPixel) = 0;
            else
               *(colPixel) = (byte)(*(colPixel) - invertedAlpha);
            colPixel += 4;
         }
         rowPixel += stride;
      }
   } 
   finally 
   {
      if (data != null)
         image.UnlockBits(data);
   }
}

SqlConnection conn= new SqlConnection("urconnectionstrng");<br />
DataSet dst = new DataSet();<br />
SqlDatAdapter dap = new SqlDataAdapter("select CustomerId from Customers",conn);<br />
comboBox1.DataSource =dst.Tables[0];<br />
comboBox1.DisplayMember="CustomerId"; <br />
comboBox1.ValueMember="CustomerId"; <br />
<br />
MessageBox.Show ("Item is"+ comboBox1.Items[1].ToString());