運行查詢時用戶被拒絕訪問

-1

我的vb.net代碼應該連接到我的數據庫。它直到我添加了一個查詢來檢查用戶名和密碼是否存在。添加後，用戶被拒絕訪問，同時仍然使用相同的密碼。這可能是什麼原因？代碼：運行查詢時用戶被拒絕訪問

MysqlConn = New MySqlConnection() 

    MysqlConn.ConnectionString = "server=;" _ 
    & "user id=;" _ 
    & "password=;" _ 
    & "database=" 

    Try 
     MysqlConn.Open() 
     Using cmd As New MySqlCommand 
      cmd.CommandText = "SELECT COUNT(*) From tableUser WHERE Username=" & TextBox1.Text & " AND Password=" & TextBox2.Text 
      cmd.CommandType = CommandType.Text 
      cmd.Connection = MysqlConn 
      result = cmd.ExecuteScalar 
     End Using 
     MysqlConn.Close() 
     If (result < 1) Then 
      MessageBox.Show("Please make sure you have typed valid credentials!") 
     ElseIf result = 1 Then 
      Dim form As New Form2 
      form.Show() 
      Me.Close() 
     End If 
    Catch myerror As MySqlException 
     MessageBox.Show("Connection to the database has been lost. Please try again later.") 
    Finally 
     MysqlConn.Dispose() 
    End Try

來源

2017-01-31 Matt142

*請*使用參數化查詢**查看**。 *停止在數據庫中以純文本格式存儲密碼！*您的代碼只是乞求[Bobby Tables]（http://bobby-tables.com/）來訪問。 – Siyual

這裏沒有足夠的信息。準確地說，用戶在什麼時候拒絕訪問？當你運行下一個查詢？發佈確切的錯誤消息和代碼出現的位置。上面的註釋重新安全和SQL注入也是非常有效的，btw – ADyson

是的，我知道關於以純文本存儲它們，這純粹是作爲一個測試:) – Matt142

這裏有一些代碼，我只是寫它，希望它有幫助，只是改變它的需要。

Private Sub login() 
    conn = New MySqlConnection 
    con.ConnectionString = 
     "server=localhost;userid=root;password=1234;database=batabase;port=3307" 
    Dim READER As MySqlDataReader 
    If TextBox1.Text = "" Then 


     MessageBox.Show("Please enter usename ! ", "Enter username") 
     Exit Sub 

    End If 
    If TextBox2.Text = "" Then 

     MessageBox.Show("Please enter password", "Enter password") 
     Exit Sub 
    End If 


    Try 


     conn.Open() 
     Dim Query As String 
     Query = "select * from db.users where user='" & TextBox1.Text & "' and password='" & TextBox2.Text & "' " 
     COMMAND = New MySqlCommand(Query, conn) 
     READER = COMMAND.ExecuteReader 
     Dim count As Integer 

     count = 0 
     While READER.Read 
      count = count + 1 
     End While 

     If count = 1 Then 

      Form.Show() 
      Me.Hide() 

     ElseIf count > 1 Then 
      MessageBox.Show("The username is already in use!") 
     Else 
      MsgBox("Error , please try again ", MsgBoxStyle.Critical) 
     End If 




     conn.Close() 
    Catch ex As Exception 
     MessageBox.Show(ex.Message) 
    Finally 
     conn.Dispose() 
    End Try 
End Sub

將數據庫名稱用戶名更改爲您的需要，它將工作！

只需在您的表單上添加登錄按鈕（）即可！或在您的按鈕上輸入此代碼，無需私人分站登錄（）

來源

2017-01-31 17:45:31 Trajkovski

運行查詢時用戶被拒絕訪問

回答

相關問題