[سعود]

مثال بسيط
مربع نص textbox1
زر امر button1
شبيكة بيانات datagridview باسم dgv1

وهذا الكلاس

كود :

Imports System.Data.OleDb

Public Class Form1
    Dim str As String = "provider=microsoft.ace.oledb.12.0;data source=|datadirectory|\students.accdb"
    Dim con As New OleDbConnection(str)
    Dim ds As New DataSet
    Private Sub dgds(ByVal d As DataSet)
        If dgv1.InvokeRequired Then
            dgv1.Invoke(New Action(Of DataSet)(AddressOf dgds), d)
        Else
            dgv1.DataSource = d

        End If
    End Sub
    Private Sub dgv(ByVal d As String)
        If dgv1.InvokeRequired Then
            dgv1.Invoke(New Action(Of String)(AddressOf dgv), d)
        Else
            dgv1.DataMember = d

        End If
    End Sub

    Private Sub gd()
        dgds(Nothing)
        dgv(Nothing)
        ds.Clear()
        Dim da As New OleDbDataAdapter("select id_number from s1", con)
        da.Fill(ds, "s1")
        dgds(ds)
        dgv("s1")

    End Sub
    Private Sub Form1_Load(sender As System.Object, e As System.EventArgs) Handles MyBase.Load
        begin()
    End Sub

    Private Sub begin()
        Dim ath As New Threading.Thread(AddressOf gd)
        If ath.IsAlive = False Then
            ath.Start()
        End If
    End Sub

    Private Sub Button1_Click(sender As System.Object, e As System.EventArgs) Handles Button1.Click
        If isfound(TextBox1.Text) Then
            MsgBox("الرقم محجوز", MsgBoxStyle.Critical, "")
            Exit Sub
        End If

        If addnew(TextBox1.Text) Then
            MsgBox("تم الحفظ", MsgBoxStyle.Information, "")
        Else
            MsgBox("لم يتم الحفظ لوجود خطا", MsgBoxStyle.Critical, "")

        End If


    End Sub


    Private Function isfound(ByVal txt As String) As Boolean
        Dim cm As New OleDbCommand("select count(tid) from s1 where id_number=@id_number", con)

        cm.Parameters.AddWithValue("@id_number", txt)
        If con.State = ConnectionState.Closed Then
            con.Open()
        End If
        If cm.ExecuteScalar > 0 Then
            Return True
        Else
            Return False
        End If

    End Function


    Private Function addnew(ByVal txt As String) As Boolean
        

        Dim cm As New OleDbCommand("insert into s1(id_number) values(@id_number)", con)
        cm.Parameters.AddWithValue("@id_number", txt)
        If con.State = ConnectionState.Closed Then
            con.Open()
        End If
        Try
            cm.ExecuteNonQuery()
            begin()
            Return True
        Catch ex As Exception
            Return False
        End Try

    End Function





End Class