Sql 如何在vb.net中使用try-and-catch块？

对于下面显示的代码，如果发生错误，我将如何使用try/catch块来处理错误

        TOTKILO.Text = KILO.Text * TOUCH.Text * 0.01
        TextBox10.Text = TextBox9.Text * TextBox8.Text * 0.01
        K = Math.Round(Val(TOTKILO.Text) - Val(TextBox10.Text), 5)
        TextBox11.Text = TextBox7.Text + K

        cmd.CommandType = Data.CommandType.Text
        con.ConnectionString = "Data Source=.\SQLEXPRESS;AttachDbFilename=C:\Documents and Settings\Administrator\My Documents\Visual Studio 2005\Projects\SHOPPROJECT\SHOPPROJECT\shop.mdf;Integrated Security=True;User Instance=True"
        con.Open()
        If RadioButton1.Checked Then
            GOLD = 1
        ElseIf RadioButton2.Checked Then
            SILVER = 1
        End If
        If RadioButton3.Checked Then
            KGOLD = 1
        ElseIf RadioButton4.Checked Then
            KSILVER = 1
        End If
        cmd.CommandText = " INSERT INTO SALES VALUES('" & ComboBox1.Text & " ' , " & SILVER & " ," & GOLD & ",'" & ComboBox2.Text & "'," & KILO.Text & ", " & TOUCH.Text & " ," & TOTKILO.Text & "," & TextBox3.Text & "," & TextBox8.Text & "," & KGOLD & "," & KSILVER & "," & TextBox9.Text & " ," & TextBox10.Text & "," & TextBox11.Text & "," & TextBox12.Text & " , " & TextBox13.Text & " ) "
        cmd.CommandType = " UPDATE BALANCE SET OBBALANCE = " & TextBox11.Text & " WHERE CUSTOMERNAME = '" & ComboBox1.Text & "' "
        cmd.Connection = con
        cmd.ExecuteNonQuery()
        con.Close()
END SUB

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我使用VB.Net控件和LINQ to SQL来执行所有更新和插入，因此当出现错误时，我想显示“正确输入数据”，一旦捕获到异常，我该如何执行该操作？

我在下面添加了一个简单的Try…catch，但我想您会发现您有很多问题：

• 如果您似乎在对字符串对象执行乘法运算，则应首先解析出数字，然后根据需要将其转换回字符串对象
• 您还将CommandType设置两次，并在第二个实例中设置为更新命令，而不是适当的值
• 您的代码对SQL注入非常开放，您不应该通过字符串连接来构建SQL语句，而应该使用sqlparameters
• 如果要进行字符串连接，请至少使用字符串生成器，但不要进行字符串连接（参见上文）
• 一次性对象（如SQLCommand）需要放置在使用块中
• 不要用大写字母发帖
• 只发布一次问题，如果您想添加详细信息，可以在发布问题后编辑问题

以下是修改后的代码：

Try
    TOTKILO.Text = KILO.Text * TOUCH.Text * 0.01
    TextBox10.Text = TextBox9.Text * TextBox8.Text * 0.01
    K = Math.Round(Val(TOTKILO.Text) - Val(TextBox10.Text), 5)
    TextBox11.Text = TextBox7.Text + K
    cmd.CommandType = Data.CommandType.Text
    con.ConnectionString = "Data Source=.\SQLEXPRESS;AttachDbFilename=C:\Documents and Settings\Administrator\My Documents\Visual Studio 2005\Projects\SHOPPROJECT\SHOPPROJECT\shop.mdf;Integrated Security=True;User Instance=True"
    con.Open()
    If RadioButton1.Checked Then
        GOLD = 1
    ElseIf RadioButton2.Checked Then
        SILVER = 1
    End If
    If RadioButton3.Checked Then
        KGOLD = 1
    ElseIf RadioButton4.Checked Then
        KSILVER = 1
    End If
    cmd.CommandText = " INSERT INTO SALES VALUES('" & ComboBox1.Text & " ' , " & SILVER & " ," & GOLD & ",'" & ComboBox2.Text & "'," & KILO.Text & ", " & TOUCH.Text & " ," & TOTKILO.Text & "," & TextBox3.Text & "," & TextBox8.Text & "," & KGOLD & "," & KSILVER & "," & TextBox9.Text & " ," & TextBox10.Text & "," & TextBox11.Text & "," & TextBox12.Text & " , " & TextBox13.Text & " ) "
    cmd.CommandType = " UPDATE BALANCE SET OBBALANCE = " & TextBox11.Text & " WHERE CUSTOMERNAME = '" & ComboBox1.Text & "' "
    cmd.Connection = con
    cmd.ExecuteNonQuery()
Catch (ex as Exception)
    MsgBox.Show("Enter Data Correctly: " & ex.toString)
Finally
    con.Close()
End Try

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请你不要对每一个可能重复的问题大喊大叫，也不要把同一个问题贴两次！我试着在编辑中整理一下…我能说什么我是受虐狂呢？你们要投票来结束他的一个问题，让它成为另一个问题。这本书至少尝试了一些可读性。