为多个文本框字段vb2010创建错误检查

时间：2014-11-02 17:21:21

标签： vb.net-2010 error-checking

我是VB的新手，我正在尝试扩展我们在课堂上创建的BASIC256程序。我成功创建了应用程序的控制台版本（下面的代码）和Windows窗体版本。我需要帮助创建文本框的错误检查。对于TextBox1，我希望防止出现空白字段。对于TextBox3，我想要一个正数，不超过2位小数。此外，我知道代码可能过于复杂，任何清洁建议将不胜感激。

控制台代码

Module Module1

Sub Main()
    Dim check_num(10) As String
    Dim description(10) As String
    Dim amount(10) As Decimal
    Dim total_bal(10) As Decimal
    Dim pointer As Integer
    Dim x As Integer

    pointer = 0

start:
    Console.Clear()
    Console.WriteLine("Enter check number for a check")
    Console.WriteLine("Enter B for a balance inquiry")
    Console.WriteLine("Enter C for a bank charge")
    Console.WriteLine("Enter D for a deposit")
    Console.WriteLine("Enter F if you are finished")
    Console.WriteLine("Enter choice: ")
    check_num(pointer) = Console.ReadLine()

    Select Case check_num(pointer)
        Case "B", "b"
            x = 0
            For x = 0 To 10
                If total_bal(x) = 0 Then
                    x = x - 1
                    If x < 0 Then
                        x = 0
                    End If
                Else
                    If total_bal(x) <> 0 Then
                        GoTo cont
                    End If
                End If
                Console.WriteLine("Balance is: {0}", total_bal(x))
                Console.WriteLine("Press any key to continue...")
                Console.ReadKey(True)
                GoTo start
cont:
            Next x
        Case "D", "d"
            x = 0
            For x = 0 To 10
                If total_bal(x) = 0 Then
                    Console.WriteLine("Amount of deposit: ")
                    amount(x) = Console.ReadLine()

                    Console.WriteLine("Descripiton of transaction: ")
                    description(x) = Console.ReadLine()
                    If x = 0 Then
                        total_bal(x) = total_bal(x) + amount(x)
                    Else
                        total_bal(x) = total_bal(x - 1) + amount(x)
                    End If
                    GoTo start
                End If
            Next x

        Case "F", "f"
            End
        Case Else
            x = 0
            For x = 0 To 10
                If total_bal(x) = 0 Then
                    Console.WriteLine("Amount of debit: ")
                    amount([x]) = Console.ReadLine()
                    Console.WriteLine("Descripiton of transaction: ")
                    description$([x]) = Console.ReadLine()
                    If x = 0 Then
                        total_bal(x) = total_bal(x) - amount(x)
                    Else
                        total_bal(x) = total_bal(x - 1) - amount(x)
                    End If
                    GoTo start
                End If
            Next x
    End Select
    GoTo start
End Sub

End Module

Windows窗体代码

Public Class Form1
Dim check_num(10) As String
Dim description(10) As String
Dim amount(10) As Decimal
Dim total_bal(10) As Decimal
Dim pointer As Integer = 0
Dim x As Integer

Private Sub RadioButton1_CheckedChanged(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles RadioButton1.CheckedChanged
    If RadioButton1.Checked = True Then
        Label3.Visible = True
        TextBox3.Visible = True
        Label2.Visible = True
        TextBox1.Visible = True
        Button1.Visible = True
    End If
End Sub

Private Sub RadioButton2_CheckedChanged(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles RadioButton2.CheckedChanged
    If RadioButton2.Checked = True Then
        Label3.Visible = True
        TextBox3.Visible = True
        Label2.Visible = True
        TextBox1.Visible = True
        Button1.Visible = True
    End If
End Sub

Private Sub RadioButton3_CheckedChanged(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles RadioButton3.CheckedChanged
    If RadioButton3.Checked = True Then
        Label3.Visible = True
        TextBox3.Visible = True
        Label2.Visible = True
        TextBox1.Visible = True
        Button1.Visible = True
    End If
End Sub

Private Sub RadioButton4_CheckedChanged(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles RadioButton4.CheckedChanged
    If RadioButton4.Checked = True Then
        Label3.Visible = False
        TextBox3.Visible = False
        Label2.Visible = False
        TextBox1.Visible = False
        Button1.Visible = False
    End If

    x = 0
    For x = 0 To 10
        If total_bal(x) = 0 Then
            x = x - 1
            If x < 0 Then
                x = 0
            End If
            GoTo Line1
        End If
    Next x
Line1:
    Label4.Visible = True
    TextBox2.Visible = True
    TextBox2.Text = total_bal(x).ToString("n2")
    MessageBox.Show("Press OK to clear the screen.")
    Label4.Visible = False
    TextBox2.Visible = False
    RadioButton4.Checked = False
End Sub

Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
    If RadioButton1.Checked = True Then
        x = 0
        For x = 0 To 10
            If total_bal(x) = 0 Then
                If TextBox3.Text <> String.Empty Then
                    If Not Decimal.TryParse(TextBox3.Text, amount(x)) Then
                        MessageBox.Show("Please use 12345.67 format only.")
                        TextBox3.Focus()
                    Else
                        amount(x) = TextBox3.Text
                        description(x) = TextBox1.Text
                        GoTo Line1
                    End If
                End If
            End If
        Next x
Line1:
        If x = 0 Then
            total_bal(x) = total_bal(x) - amount(x)
        Else
            total_bal(x) = total_bal(x - 1) - amount(x)
        End If
        MessageBox.Show("Check Number " & description(x) & " was withdrawn" & vbCrLf & "in the amount of $" & amount(x))
    End If
    If RadioButton2.Checked = True Then
        x = 0
        For x = 0 To 10
            If total_bal(x) = 0 Then
                If TextBox3.Text <> String.Empty Then
                    If Not Decimal.TryParse(TextBox3.Text, amount(x)) Then
                        MessageBox.Show("Please use 12345.67 format only.")
                        TextBox3.Focus()
                    Else
                        amount(x) = TextBox3.Text
                        description(x) = TextBox1.Text
                        GoTo Line2
                    End If
                End If
            End If
        Next x
Line2:
        If x = 0 Then
            total_bal(x) = total_bal(x) - amount(x)
        Else
            total_bal(x) = total_bal(x - 1) - amount(x)
        End If
        MessageBox.Show("A fee for " & description(x) & " was withdrawn" & vbCrLf & "in the amount of $" & amount(x))
    End If
    If RadioButton3.Checked = True Then
        x = 0
        For x = 0 To 10
            If total_bal(x) = 0 Then
                If TextBox3.Text <> String.Empty Then
                    If Not Decimal.TryParse(TextBox3.Text, amount(x)) Then
                        MessageBox.Show("Please use 12345.67 format only.")
                        TextBox3.Focus()
                    Else
                        amount(x) = TextBox3.Text
                        description(x) = TextBox1.Text
                        GoTo Line3
                    End If
                End If
            End If
        Next x
Line3:
        If x = 0 Then
            total_bal(x) = total_bal(x) + amount(x)
        Else
            total_bal(x) = total_bal(x - 1) + amount(x)
        End If
        MessageBox.Show("A deposit for " & description(x) & " was made" & vbCrLf & "in the amount of $" & amount(x))
    End If
    RadioButton1.Checked = False
    RadioButton2.Checked = False
    RadioButton3.Checked = False
    RadioButton4.Checked = False
    TextBox1.Clear()
    TextBox2.Clear()
    TextBox3.Clear()
    Label3.Visible = False
    TextBox3.Visible = False
    Label2.Visible = False
    TextBox1.Visible = False
    Button1.Visible = False

End Sub

Private Sub Button2_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button2.Click
    Dim Response As Integer
    Response = MessageBox.Show("Do you really want to exit?", "", _
                               MessageBoxButtons.YesNo, MessageBoxIcon.Question)
    If Response = vbYes Then
        Me.Close()
    End If
End Sub

Private Sub Button3_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button3.Click
    RadioButton1.Checked = False
    RadioButton2.Checked = False
    RadioButton3.Checked = False
    RadioButton4.Checked = False
    TextBox1.Clear()
    TextBox2.Clear()
    TextBox3.Clear()
    Array.Clear(check_num, 0, check_num.Length)
    Array.Clear(description, 0, description.Length)
    Array.Clear(amount, 0, amount.Length)
    Array.Clear(total_bal, 0, total_bal.Length)
End Sub

End Class

1 个答案:

答案 0 :(得分：0)

对于textbox1，请检查您在该特定文本框中使用的任何按钮。检查将是这样的

If textbox1.text = String.Empty (or you can use "") Then
 'Throw an error of some sort
End If

对于textbox2，为该文本框添加一个KeyPress事件处理程序。它看起来像这样

Private Sub textbox1_KeyPress(sender As System.Object, e As System.Windows.Forms.KeyPressEventArgs) Handles txtbox1.KeyPress

Dim iKeyPress as Integer = Asc(e.KeyChar)
Dim hasDecimal as Boolean = False

IF iKeyPress < 48 Or iKeyPress > 57 Then ' Only Allow Numbers
    e.Handled = True
End If
Select Case iKeyPress
Case 46 'Decimal
    If hasDecimal = False Then
        e.Handled = True
        hasDecimal = True
    End If
End Select




End Sub
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