loginform.vb

这是一个固定资产管理系统的源代码

Imports System.Data.SqlClient
Public Class LoginForm
    '记录用户登录次数
    Private MyTryCount As Integer = 0
    Private Sub 登录系统Button_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles 登录系统Button.Click
        Dim MySQLConnectionString As String = My.Settings.MyAssetsConnectionString
        Dim MySQL As String = "Select COUNT(*) From 操作用户 Where 用户名称=@用户名称 AND 用户密码=@用户密码"
        Dim MyConnection As New SqlConnection(MySQLConnectionString)
        MyConnection.Open()
        Dim MyCommand As New SqlCommand(MySQL, MyConnection)
        MyCommand.Parameters.Clear()
        Dim MySqlNameParameter As New SqlParameter()
        MySqlNameParameter.ParameterName = "@用户名称"
        MySqlNameParameter.Value = Me.用户名称TextBox.Text
        MyCommand.Parameters.Add(MySqlNameParameter)
        Dim MySqlPWParameter As New SqlParameter()
        MySqlPWParameter.ParameterName = "@用户密码"
        MySqlPWParameter.Value = Me.用户密码TextBox.Text
        MyCommand.Parameters.Add(MySqlPWParameter)
        Dim MyCount As Integer = MyCommand.ExecuteScalar()
        If (MyCount = 1) Then
            Me.Close()
        Else
            Me.MyTryCount += 1
            If (Me.MyTryCount <> 3) Then
                Dim MyDoCount As Integer = 3 - Me.MyTryCount
                MessageBox.Show("用户密码或用户名称有错，还有" + MyDoCount + "次机会！", "信息提示", MessageBoxButtons.OK, MessageBoxIcon.Information)
                Me.用户密码TextBox.Text = ""
                Me.用户名称TextBox.Text = ""
            Else
                退出系统Button_Click(Nothing, Nothing)
            End If
        End If
        If (MyConnection.State = ConnectionState.Open) Then
            MyConnection.Close()
        End If
    End Sub

    Private Sub 退出系统Button_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles 退出系统Button.Click
        Dim MyDlg As MainForm = Me.Owner
        MyDlg.Close()
    End Sub
End Class