内容:
最后，请看完整的代码：
    using System;
    using System.WinForms;
    
    public class TempConverter : System.WinForms.Form 
{

       Label   lTempFah = new Label();
       Label   lTempCel = new Label();
       TextBox tTempFah = new TextBox();
       TextBox tTempCel = new TextBox();
       Button  bnCtoF = new Button();
       Button  bnFtoC = new Button();

       public TempConverter() {
          this.SetSize(180,90);
          this.BorderStyle = 
FormBorderStyle.FixedDialog;
          this.Text = " +C －> +F /  +F －> +C ";
          this.StartPosition = 
FormStartPosition.CenterScreen;
          this.HelpButton = false;
          this.MaximizeBox = false;
          tTempCel.TabIndex = 0;
          tTempCel.SetSize(50,25);
          tTempCel.SetLocation(13,5);
          lTempCel.TabStop = false;
          lTempCel.Text = "C";
          lTempCel.SetSize(25, 25);
          lTempCel.SetLocation(65,5);
          tTempFah.TabIndex = 1;
          tTempFah.SetSize(50,25);
          tTempFah.SetLocation(90,5);
          lTempFah.TabStop = false;
          lTempFah.Text = "F";
          lTempFah.SetSize(25,25);
          lTempFah.SetLocation(142,5);
          bnCtoF.TabIndex = 2;
          bnCtoF.Text = "C to F";
          bnCtoF.SetSize(70,25);
          bnCtoF.SetLocation(13,35);
          bnCtoF.Click += new EventHandler
(this.bnCtoF_Click);
          bnFtoC.TabIndex = 3;
          bnFtoC.Text = "F to C";
          bnFtoC.SetSize(70,25);
          bnFtoC.SetLocation(90,35);
          bnFtoC.Click += new EventHandler
(this.bnFtoC_Click);
          this.Controls.Add(tTempCel);
          this.Controls.Add(lTempCel);
          this.Controls.Add(tTempFah);
          this.Controls.Add(lTempFah);
          this.Controls.Add(bnCtoF);
          this.Controls.Add(bnFtoC);
       //= new Control [] { tTempCel, lTempCel, tTempFah, 
lTempFah, bnCtoF, bnFtoC };
       }
    
       public static void Main() {
          Application.Run( new    TempConverter() );
       }

       private void bnCtoF_Click(Object sender, 
EventArgs e) {
          double dTempCel = 0;
          double dTempFah = 0;
          try { dTempCel = tTempCel.Text.ToDouble(); }
          catch(Exception) {
             tTempCel.Clear();
             tTempFah.Clear();
             return;
          }
          dTempFah = 1.8*dTempCel+32;
          tTempFah.Text = dTempFah.ToString();
          tTempFah.Focus();
          tTempFah.SelectionStart = 0;
          tTempFah.SelectionLength = 0;
          tTempCel.Focus();
          tTempCel.SelectionStart = 0;
          tTempCel.SelectionLength = 0;
       }
    
       private void bnFtoC_Click(Object sender, 
EventArgs e) {
          double dTempCel = 0;
          double dTempFah = 0;
          try { dTempFah = tTempFah.Text.ToDouble(); }
          catch(Exception) {
             tTempCel.Clear();
             tTempFah.Clear();
             return;
          }
          dTempCel = (dTempFah-32)/1.8;
          tTempCel.Text = dTempCel.ToString();
          tTempCel.Focus();
          tTempCel.SelectionStart = 0;
          tTempCel.SelectionLength = 0;
          tTempFah.Focus();
          tTempFah.SelectionStart = 0;
          tTempFah.SelectionLength = 0;
       }
    }