[vbnet]

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تم تعديل الكود للفورم1

كما ذكر الأستاذ kslawy استخدم id المستخدم بدلا من اسمه وهو الأسلوب الصحيح

على افتراض ان:
الجدول users له الحقول التالية
id رقم
username نص
password نص
usertype نص

الجدول comments له الحقول التالية
post_id رقم
userid رقم
title نص
message نص

تم تجاهل أكواد Button1 وما بعدها

كود :

Imports MySql.Data.MySqlClient

Public Class Form1

    Private conString As String = "Server=localhost; Database=oman ;Uid=root; Pwd=;"


    Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
        GroupBox1.Enabled = True
        lbllogin.Enabled = False

    End Sub


    Private Sub btnlogin_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnlogin.Click

        'check if the textbox is equal to nothing then it will display the message below!.
        If Me.txtuname.Text = "" And Me.txtpass.Text = "" Then
            MsgBox("Password or Username Incorrect!")
            Exit Sub
        End If

        Try

            Using con As New MySqlConnection(conString)

                Dim sql As String = "SELECT * FROM `users` WHERE `username`=@username AND `password`=@password"
                Using da As New MySqlDataAdapter(sql, con)
                    da.SelectCommand.Parameters.AddWithValue("@username", Me.txtuname.Text)
                    da.SelectCommand.Parameters.AddWithValue("@password", Me.txtpass.Text)

                    Dim dt As New DataTable
                    If da.Fill(dt) > 0 Then

                        Dim row As DataRow = dt.Rows(0)
                        Select Case row("usertype")

                            Case "admin"
                                'welcomes the user as Admiistrator
                                MsgBox("Welcome " & row("username") & " you login as Administrator ")
                                'set the lbllogin text to Logout
                                'disabled the groupbox
                                Me.GroupBox1.Enabled = False
                                'reset all the two textbox
                                'set the lblname to the specific user
                                Me.lblname.Text = "Hi, " & row("username")

                            Case "Encoder"
                                MsgBox("Welcome " & row("username") & " you login as Encoder ")
                                Me.GroupBox1.Enabled = True
                                Me.lblname.Text = "Hi, " & row("username")

                            Case Else
                                MsgBox("You login as Guest!")
                                Me.GroupBox1.Enabled = False
                                Me.lblname.Text = "Hi, " & row("username")
                                Me.lbllogin.Enabled = True
                                Me.DataGridView1.Visible = True

                        End Select

                        Me.lbllogin.Enabled = True
                        Me.lbllogin.Text = "Logout"

                        ViewUserComments(row("id"))

                    Else
                        MsgBox("Contact administrator to registered!")
                    End If

                    Me.txtuname.Text = ""
                    Me.txtpass.Text = ""

                End Using
            End Using


        Catch ex As Exception
            MsgBox(ex.Message)

        End Try



    End Sub


    Private Sub ViewUserComments(userid As String)
        Using con As New MySqlConnection(conString)
            Using da As New MySqlDataAdapter("SELECT * FROM `comments` WHERE `userid`=@userid ", con)
                da.SelectCommand.Parameters.AddWithValue("@userid", userid)
                Using dt As New DataTable
                    If da.Fill(dt) > 0 Then

                        DataGridView1.DataSource = dt

                        DataGridView1.Columns(0).HeaderText = "ID"
                        DataGridView1.Columns(0).Width = 50
                        DataGridView1.Columns(1).HeaderText = "added by"
                        DataGridView1.Columns(1).Width = 150
                        DataGridView1.Columns(2).HeaderText = "Name Thread"
                        DataGridView1.Columns(2).Width = 200
                        DataGridView1.Columns(3).HeaderText = "Notes"
                        DataGridView1.Columns(3).Width = 200

                        DataGridView1.Columns(1).DataGridView.Name = "& name"

                    End If

                End Using
            End Using
        End Using

    End Sub


    Private Sub lbllogin_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles lbllogin.Click

        If Me.lbllogin.Text = "Logout" Then
            Me.DataGridView1.DataSource = Nothing
            Me.lbllogin.Enabled = False
            Me.lbllogin.Text = "Login"
            Me.lblname.Text = "Hi, Guest!"
            Me.GroupBox1.Enabled = True
        End If
    End Sub





    Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click, Button1.Click
        PrintDocument1.Print()
    End Sub
    Private Sub PrintDocument1_PrintPage(ByVal sender As System.Object, ByVal e As System.Drawing.Printing.PrintPageEventArgs) Handles PrintDocument1.PrintPage

        Dim bm As New Bitmap(Me.DataGridView1.Width, Me.DataGridView1.Height)

        DataGridView1.DrawToBitmap(bm, New Rectangle(0, 0, Me.DataGridView1.Width, Me.DataGridView1.Height))

        e.Graphics.DrawImage(bm, 0, 0)

    End Sub


    Private Sub Button2_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button2.Click

        Dim connectionString As String = "Data Source=.;Initial Catalog=pubs;Integrated Security=True"

        Dim sql As String = "SELECT * FROM comments"



        Dim ds As New DataSet()


        DataGridView1.DataSource = ds

        DataGridView1.DataMember = "comments"

    End Sub


End Class

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