检查此

Hi ,
Check this

 double sum = 0;
 foreach (Control c in this.Controls)
 {
     if (c is GroupBox)
     {
         foreach (Control item in c.Controls)
         {
             if (item is TextBox)
             {
                 sum += Convert.ToDouble(((TextBox)item).Text);
             }
         }
     }
 }

MessageBox.Show(sum.ToString());

***的问候
M.Mitwalli

Best Regards
M.Mitwalli

试试这个

Hi,

try this

double sum=double.Parse(textBox21.Text)+ double.Parse(textBox22.Text)+double.Parse(textBox23.Text)+ double.Parse(textBox24.Text)+.............+double.Parse(textBox29.Text)+ double.Parse(textBox30.Text) 

textBox31.Text =sum.toString();