輸入內容(string類型的)，統計字母/數字/空格的數量 [C#]

1. 來張 效果圖 （簡陋的界面 湊合著看吧）

2. 代碼
[csharp] www.2cto.com
private void button1_Click(object sender, EventArgs e) 
       { 
           string sin = txtsid.Text; 
           int alpha = 0; 
           int num = 0; 
           int spc = 0; 
           for (int i = 0; i < sin.Length; i++) 
           { 
               string ch = sin.Substring(i, 1); 
               if (ch == " ") 
                   spc += 1; 
               else if (char.IsNumber(ch, 0)) 
               { 
                   num += 1; 
               } 
               else if (char.IsUpper(ch, 0) | char.IsLower(ch, 0)) 
               { 
                   alpha += 1; 
               } 
 
           } 
           MessageBox.Show("空格=" + spc + ",數字=" + num + ",字母=" + alpha); 
 
       }