.net简单计算器的问题（有代码）
Private Sub Page_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
AddHandler Me.btnAdd.Click, AddressOf Calculate
AddHandler Me.btnSubtract.Click, AddressOf Calculate
AddHandler Me.btnMultiply.Click, AddressOf Calculate
AddHandler Me.btnDivide.Click, AddressOf Calculate
End Sub
Public Sub Calculate(ByVal sender As Object, ByVal e As System.EventArgs)
Dim op1 As Integer = CType(Me.TextBox1.Text, Integer)
Dim op2 As Integer = CType(Me.TextBox2.Text, Integer)
Dim result As Integer
Select Case CType(sender, button).CommandName
Case "Add "
result = op1 + op2
Case "Subtract "
result = op1 - op2
Case "Multiply "
result = op1 * op2
Case "Divide "
' Divide two numbers and return an integer result.
If op2 > 0 Then
result = op1 \ op2
Else
result = 0
End If
Case Else
' Error handling code here.
End Select
Label2.Text = result.ToString()
End Sub
运行是，提示：Select Case CType(sender, button).CommandName出错，请问该怎么改，谢谢！
[解决办法]
先保存在一个string中,再case
[解决办法]
一大堆if...elseif...的代码可以说是豆腐渣工程。
你要明确自己的设计思维到底倾向于哪个方向，到底是方法依据对象来分别定义（对不同类型的btn重载不同的Calculate），还是对象依据方法来定义（你那种把几种类型拼在方法内的做法）。
[解决办法]
运行是，提示：Select Case CType(sender, button).CommandName出错，请问该怎么改，谢谢！
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悄悄地说一句对于vb代码的语法格式有点不太熟悉
应该是你的前台代码有问题了，前面加了CommandName CommandArgument OnCommand
<asp:Button id= "btnAdd " runat= "server " Text= "+ " CommandName= "Add " OnCommand= "btnAdd_Click " > </asp:Button>
.....................后面的不一一列举了
<asp:Button id= "btnSubtract " runat= "server " Text= "+ " CommandName= "Subtract " > </asp:Button>
<asp:Button id= "btnMultiply " runat= "server " Text= "+ " CommandName= "Multiply "> </asp:Button>
<asp:Button id= "btnDivide " runat= "server " Text= "+ " CommandName= "Divide "> </asp:Button>
这里有一个msdn示例了
ms-help://MS.VSCC.2003/MS.MSDNQTR.2003FEB.2052/cpref/html/frlrfSystemWebUIWebControlsButtonClassCommandNameTopic.htm
<%@ Page Language= "C# " AutoEventWireup= "True " %>
<html>
<head>
<script runat= "server ">
void CommandBtn_Click(Object sender, CommandEventArgs e)
{
switch(e.CommandName)
{
case "Sort ":
// Call the method to sort the list.
Sort_List((String)e.CommandArgument);
break;
case "Submit ":
// Display a message for the Submit button being clicked.
Message.Text = "You clicked the Submit button ";
// Test whether the command argument is an empty string ( " ").
if((String)e.CommandArgument == " ")
{
// End the message.
Message.Text += ". ";
}
else
{
// Display an error message for the command argument.
Message.Text += ", however the command argument is not recogized. ";
}
break;
default:
// The command name is not recognized. Display an error message.
Message.Text = "Command name not recogized. ";
break;
}
}
void Sort_List(string commandArgument)
{
switch(commandArgument)
{
case "Ascending ":
// Insert code to sort the list in ascending order here.
Message.Text = "You clicked the Sort Ascending button. ";
break;
case "Descending ":
// Insert code to sort the list in descending order here.
Message.Text = "You clicked the Sort Descending button. ";
break;
default:
// The command argument is not recognized. Display an error message.
Message.Text = "Command argument not recogized. ";
break;
}
}
</script>
</head>
<body>
<form runat= "server ">
<h3> Button CommandName Example </h3>
Click on one of the command buttons.
<br> <br>
<asp:Button id= "Button1 "
Text= "Sort Ascending "
CommandName= "Sort "
CommandArgument= "Ascending "
OnCommand= "CommandBtn_Click "
runat= "server "/>
<asp:Button id= "Button2 "
Text= "Sort Descending "
CommandName= "Sort "
CommandArgument= "Descending "
OnCommand= "CommandBtn_Click "
runat= "server "/>
<br> <br>
<asp:Button id= "Button3 "
Text= "Submit "
CommandName= "Submit "
OnCommand= "CommandBtn_Click "
runat= "server "/>
<asp:Button id= "Button4 "
Text= "Unknown Command Name "
CommandName= "UnknownName "
CommandArgument= "UnknownArgument "
OnCommand= "CommandBtn_Click "
runat= "server "/>
<asp:Button id= "Button5 "
Text= "Submit Unknown Command Argument "
CommandName= "Submit "
CommandArgument= "UnknownArgument "
OnCommand= "CommandBtn_Click "
runat= "server "/>
<br> <br>
<asp:Label id= "Message " runat= "server "/>
</form>
</body>
</html>
