calculator.cs

asp.net经典案例资料

using System;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;

namespace snowy
{
  public class Calculator : Control , INamingContainer
  {
    private TextBox txtDisplay;
    public int Result
    {
      get
      {
        if( ViewState["Result"] == null )
        {
          ViewState["Result"] = 0;
          return 0;
        }
        else
          return (int)ViewState["Result"];
      }
      set
      {
        ViewState["Result"] = value;
      }
    }

    private string Status
    {
      get
      {
        if( ViewState["Status"] == null )
        {
          ViewState["Status"] = "number1input";
          return "number1input";
        }
        else
          return (string)ViewState["Status"];
      }
      set
      {
        ViewState["Status"] = value;
      }
    }

    private void HandleDigit(string digit)
    {
      txtDisplay.Text += digit;
      if( Status == "number1input" )
      {
        Result = int.Parse(txtDisplay.Text);
      }
    }

    protected override bool OnBubbleEvent(object sender, EventArgs e)
    {
      if(sender is Button)
      {
        string text = ((Button)sender).Text.Trim();
        switch(text)
        {
          case "+":
            if(Status == "number1input")
            {
              Status = "number2input";
              txtDisplay.Text = "";
            }
            else
            {
              Result = Result + int.Parse(txtDisplay.Text);
              txtDisplay.Text = "";
            }
            break;
          case "=":
            if( Status == "number2input" )
            {
              Status = "number1input";
              txtDisplay.Text = (Result + int.Parse(txtDisplay.Text)).ToString();
              Result = int.Parse(txtDisplay.Text);
            }
            break;
          default:
            HandleDigit(text);
            break;
        }
      }
      return true;
    }

    private TableCell CreateButtonCell(string text)
    {
      TableCell cell = new TableCell();
      Button button = new Button();
      button.Text = text;
      cell.Controls.Add(button);
      return cell;
    }

    protected override void CreateChildControls()
    {
      txtDisplay = new TextBox();
      txtDisplay.ReadOnly = true;
      Controls.Add(txtDisplay);
      Controls.Add(new LiteralControl("<br/>"));

      Table table = new Table();
      TableRow row;

      row = new TableRow();
      row.Cells.Add(CreateButtonCell("  1  "));
      row.Cells.Add(CreateButtonCell("  2  "));
      row.Cells.Add(CreateButtonCell("  3  "));
      row.Cells.Add(CreateButtonCell("  4  "));
      table.Rows.Add(row);

      row = new TableRow();
      row.Cells.Add(CreateButtonCell("  5  "));
      row.Cells.Add(CreateButtonCell("  6  "));
      row.Cells.Add(CreateButtonCell("  7  "));
      row.Cells.Add(CreateButtonCell("  8  "));
      table.Rows.Add(row);

      row = new TableRow();
      row.Cells.Add(CreateButtonCell("  9  "));
      row.Cells.Add(CreateButtonCell("  0  "));
      row.Cells.Add(CreateButtonCell("  +  "));
      row.Cells.Add(CreateButtonCell("  =  "));
      table.Rows.Add(row);

      Controls.Add(table);
    }
  }
}