如何驗證VB.NET登錄窗體的放射按鈕？

Question

請幫忙。我有一個用戶名（文本框名稱txtUsername），密碼（文本框名稱txtPassword）和3個單選按鈕（rbAdmin，rbSec和rbTreasure）的VB.NET登錄表單。用戶名和密碼值取自SQL Server數據庫表UserDetails。登錄表單允許用戶使用正確的用戶名和密碼以及正確的單選按鈕的正確組合登錄。

EG如果我的用戶名是'john'，密碼是'johns'，我是祕書。選中的單選按鈕rbSec）

我只設法驗證用戶名和密碼，因爲我已經失敗了單選按鈕後登錄有人能幫助請在下面的代碼是我曾嘗試：。

Imports System.Data.OleDb 
Public Class frmLogin 

    Private Sub OK_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles OK.Click 
     Try 
      If txtUsername.Text = "" Then 
       MsgBox("All fields are required.") 
       Return 
      ElseIf txtPassword.Text = "" Then 
       MsgBox("All fields are required.") 
       Return 
      ElseIf rbAdmin.Checked = False And rbSec.Checked = False And rbTreasurer.Checked = False Then 
       MessageBox.Show("Select the user type!", "WARNING", MessageBoxButtons.OK, MessageBoxIcon.Exclamation) 
       Using conn As New OleDbConnection("Data Source=JUNIOR-PC;Initial Catalog=TBSociety;Persist Security Info=True;User ID=sa;Password=adminadmin") 
        conn.Open() 

        Dim command As New OleDbCommand("SELECT COUNT(*) FROM UserDetails where UserName = '" & txtUsername.Text & "' and Password = '" & txtPassword.Text & "' ", conn) 
        Dim adapter As New OleDbDataAdapter 
        Dim ds As New DataSet 
        adapter.SelectCommand = command 
        adapter.Fill(ds, "UserDetails") 

        If ds.Tables("UserDetails").Rows.Count > 0 And ds.Tables("UserDetails").Rows.Count < 2 Then 
         If rbAdmin.Checked = True Then 
          Me.Hide() 
          frmHome.Show() 
         ElseIf rbSec.Checked = True Then 
          MsgBox("You will have limited access to parts of the system.") 
          Me.Hide() 
          frmHome.Show() 
         End If 

        End If 

       End Using 

      End If 
      Me.Hide() 
      frmHome.Show() 
     Catch ex As Exception 
      MessageBox.Show(ex.Message, "ERROR5", MessageBoxButtons.OK, MessageBoxIcon.Error) 
     End Try 
    End Sub 
End Class 

---

這是根據您的建議@Pradeep Kumar修改後的代碼。但是在運行時，我收到一條錯誤消息，其內容爲「必須聲明標量變量@用戶名」。請在此再糾正一次。我只是認爲它是一個我不能糾正的愚蠢錯誤。

Private Sub OK_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles OK.Click 
    Try 
     If txtUsername.Text = "" Then 
      MsgBox("All fields are required.") 
      Return 
     ElseIf txtPassword.Text = "" Then 
      MsgBox("All fields are required.") 
      Return 
     ElseIf Not rbAdmin.Checked AndAlso Not rbSec.Checked AndAlso Not rbTreasurer.Checked Then 
      MessageBox.Show("Select the user type!", "WARNING", MessageBoxButtons.OK, MessageBoxIcon.Exclamation) 
     Else 
      Dim recordsFound As Integer 
      Using conn As New OleDbConnection("Provider=SQLOLEDB.1;Data Source=Junior-PC;Persist Security Info=True;User ID=sa;Password=adminadmin;Initial Catalog=TBSociety") 
       conn.Open() 

       Dim command As New OleDbCommand("SELECT COUNT(*) FROM Logins where Username = @Username and Password = @Password and Designation = @Designation", conn) 
       If rbAdmin.Checked Then 
        command.Parameters.AddWithValue("@Designation", "Admin") 
       ElseIf rbSec.Checked Then 
        command.Parameters.AddWithValue("@Designation", "Secretary") 
       ElseIf rbTreasurer.Checked Then 
        command.Parameters.AddWithValue("@Designation", "Treasurer") 
       End If 
       command.Parameters.AddWithValue("Username", txtUsername.Text) 
       command.Parameters.AddWithValue("@Password", txtPassword.Text) 
       recordsFound = command.ExecuteScalar 
      End Using 
      If recordsFound > 0 Then 
       If rbAdmin.Checked Then 
        txtUsername.Text = "" 
        txtPassword.Text = "" 
        rbAdmin.Checked = False 
        rbSec.Checked = False 
        rbTreasurer.Checked = False 
        Me.Hide() 
        frmHome.Show() 
       ElseIf rbSec.Checked Then 
        txtUsername.Text = "" 
        txtPassword.Text = "" 
        rbAdmin.Checked = False 
        rbSec.Checked = False 
        rbTreasurer.Checked = False 
        Me.Hide() 
        frmHome.AttendanceRegisterToolStripMenuItem.Enabled = False 
        frmHome.AdminTasksToolStripMenuItem.Enabled = False 
        frmHome.Show() 
       ElseIf rbTreasurer.Checked Then 
        frmHome.BackgroundImage = Image.FromFile("C:\Users\Junior\Documents\Visual Studio 2010\Projects\TBSSystem\TBSSystem\Resources\OFFISUPP.gif") 
        frmHome.BackgroundImageLayout = ImageLayout.Tile 
        frmHome.MemberToolStripMenuItem.Enabled = False 
        frmHome.MemberRecordsToolStripMenuItem.Enabled = False 
        frmHome.AttendanceRegisterToolStripMenuItem1.Enabled = False 
        frmHome.SecretarialServicesToolStripMenuItem.Enabled = False 
        frmHome.LogFileToolStripMenuItem.Enabled = False 
        frmHome.AdminTasksToolStripMenuItem.Enabled = False 
        frmHome.Show() 
       Else 
        MessageBox.Show("Invalid User Name, Password or Designation. Try again...") 
        Me.Hide() 
        frmHome.Show() 
       End If 
      End If 
     End If 
    Catch ex As Exception 
     MessageBox.Show(ex.Message, "ERROR5", MessageBoxButtons.OK, MessageBoxIcon.Error) 
    End Try 

Answer 1

1. 的Parameters建議使用過字符串拼接SQL 查詢。
2. 對於這個小任務，您不需要DataSet或DataAdapter。您可以輕鬆完成Command.ExecuteScalar，它只返回一個值。

你可以閱讀更多有關命令和參數的位置：Commands and Parameters (MSDN).

下面是一些未經測試的代碼，會爲你工作。請注意，我假定你的表有一個Designation列（varchar類型），並具有像Admin，Secretary，Treasurer這樣的值。如果情況並非如此，則需要進行適當的修改。

Private Sub OK_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles OK.Click 
    Try 
     If txtUsername.Text = "" Then 
      MsgBox("All fields are required.") 
      Return 
     ElseIf txtPassword.Text = "" Then 
      MsgBox("All fields are required.") 
      Return 
     ElseIf Not rbAdmin.Checked AndAlso Not rbSec.Checked AndAlso Not rbTreasurer.Checked Then 
      MessageBox.Show("Select the user type!", "WARNING", MessageBoxButtons.OK, MessageBoxIcon.Exclamation) 
     Else 
      Dim recordsFound As Integer 
      Using conn As New OleDbConnection("Data Source=JUNIOR-PC;Initial Catalog=TBSociety;Persist Security Info=True;User ID=sa;Password=adminadmin") 
       conn.Open() 
       Dim command As New OleDbCommand("SELECT COUNT(*) FROM UserDetails where UserName = @UserName and Password = @Password and Designation = @Designation", conn) 
       command.Parameters.AddWithValue("@UserName", txtUsername.Text) 
       command.Parameters.AddWithValue("@Password", txtPassword.Text) 
       If rbAdmin.Checked Then 
        command.Parameters.AddWithValue("@Designation", "Admin") 
       ElseIf rbSec.Checked Then 
        command.Parameters.AddWithValue("@Designation", "Secretary") 
       ElseIf rbTreasurer.Checked Then 
        command.Parameters.AddWithValue("@Designation", "Treasurer") 
       End If 
       recordsFound = CType(command.ExecuteScalar, Integer) 
      End Using 
      If recordsFound > 0 Then 
       If rbAdmin.Checked Then 
        'nothing special 
       ElseIf rbSec.Checked Then 
        MsgBox("You will have limited access to parts of the system.") 
       ElseIf rbTreasurer.Checked Then 
        MsgBox("whatever message you want to show......") 
       End If 
       Me.Hide() 
       frmHome.Show() 
      Else 
       MessageBox.Show("Invalid User Name, Password or Designation. Try again...") 
      End If 
     End If 
    Catch ex As Exception 
     MessageBox.Show(ex.Message, "ERROR5", MessageBoxButtons.OK, MessageBoxIcon.Error) 
    End Try 
End Sub