VB.NET制作SQL用户登录界面代码

    Private Sub OK_Click(sender As Object, e As EventArgs) Handles OK.Click
        If TextBox1.Text = "" Then
            MsgBox("用户名不能为空！！", , "提示")
        ElseIf TextBox2.Text = "" Then
            MsgBox("密码不能为空！！", , "提示")
        Else
            Dim sql As String = "select * from 人员表 where 用户名='" & TextBox1.Text.ToString.Trim & "' and 密码='" & TextBox2.Text.ToString.Trim & "'"
            Dim mycmd As New SqlCommand(sql, conn)
            Dim myreader As SqlDataReader
            myreader = mycmd.ExecuteReader
            If myreader.HasRows Then
                myreader.Read()
                MsgBox("登录成功！！", , "标题")
                yonghuming = myreader("用户名").ToString.Trim
                xingming = myreader("姓名").ToString.Trim
                bumen = myreader("部门").ToString.Trim
                FormMain.ToolStripStatusLabel3.Text = myreader("用户名").ToString.Trim & "(" & myreader("姓名").ToString.Trim & ")"
                Me.Close()
                FormMain.MenuStrip1.Visible = True
                FormMain.ToolStrip1.Visible = True
                If myreader("激活状态").ToString.Trim = "0" Then
                    MsgBox("检测到该用户首次登录，必需将初始密码修改！！", , "标题")
                    FormPassword.MdiParent = FormMain
                    FormPassword.Show()
                    FormPassword.TextBox1.Text = yonghuming & "(" & xingming & ")"
                ElseIf myreader("激活状态").ToString.Trim = "1" Then
                    Me.Close()
                    FormMain.MenuStrip1.Visible = True
                    FormMain.ToolStrip1.Visible = True
                End If
            Else
                MsgBox("输入用户名或密码错误，请重新输入！！", , "标题")
                TextBox1.Text = ""
                TextBox2.Text = ""
                TextBox1.Focus()
            End If
            myreader.Close()
        End If
    End Sub