รบกวน ทุกๆท่าน ช่วยแก้ปัญหา เกี่ยว combobox ของ vb.net ให้ทีค่ะ เป็นสิ่งที่ติดอยู่วันที่ 6 แล้ว ถ้าแก้ได้โปรแกรมก็จะเสร็จแล้วค่ะ

Private Sub EmpInfo()
       'Dim sql As String = "SELECT DISTINCT(EmpFrontName) FROM Employee" ตรวจสอบค่าซ้ำ
       Dim sql As String = "SELECT IDEmp,EmpFrontName FROM Employee"
   
       Cmd = New OleDbCommand(sql, con)

       Dim adapter = New OleDbDataAdapter(Cmd)

       Data = New DataSet()

       adapter.Fill(Data, "Emp")
       With NameBox
           .DataSource = Data.Tables("Emp")
           .DisplayMember = "EmpFrontName"
           .ValueMember = "IDEmp"

       End With
     
   End Sub

   Private Sub empdetial()
 On Error Resume Next  
       Dim sql As String = "SELECT * FROM Employee WHERE IDEmp = ?"

       cmd = New OleDbCommand(sql, con)
       cmd.Parameters.AddWithValue("", NameBox.SelectedValue)
       adapter = New OleDbDataAdapter(cmd)

       Data.Clear()
       adapter.Fill(Data, "Fnameinfo")

       EmpID.Text = Data.Tables("Fnameinfo").Rows(0)("IDEmp")
       name1.Text = Data.Tables("Fnameinfo").Rows(0)("EmpLastName")
       name2.Text = Data.Tables("Fnameinfo").Rows(0)("EmpNickName")
       positioning.Text = Data.Tables("Fnameinfo").Rows(0)("EmpPosition")
       duty.Text = Data.Tables("Fnameinfo").Rows(0)("EmpJob")
       Bdate.Text = Data.Tables("Fnameinfo").Rows(0)("EmpBeginDate")
       Money.Text = Data.Tables("Fnameinfo").Rows(0)("EmpSalary")
       StatusBox.Text = Data.Tables("Fnameinfo").Rows(0)("StatusEmp")

   End Sub

Private Sub EmpInfo()
       Dim sql As String = "SELECT IDEmp,EmpFrontName FROM Employee"
   
       Cmd = New OleDbCommand(sql, con)

       Dim adapter = New OleDbDataAdapter(Cmd)

       Data = New DataSet()

       adapter.Fill(Data, "Emp")
       With NameBox
           .DataSource = Data.Tables("Emp")
           .DisplayMember = "EmpFrontName"
           .ValueMember = "IDEmp"

       End With
     
   End Sub

   Private Sub empdetial()
       Try
         Dim sql As String = "SELECT * FROM Employee WHERE IDEmp = @IDEmp"

         cmd = New OleDbCommand(sql, con)
         cmd.Parameters.AddWithValue("@IDEmp", NameBox.SelectedValue)
         adapter = New OleDbDataAdapter(cmd)

         Data.Clear()
         adapter.Fill(Data, "Fnameinfo")

         EmpID.Text = Data.Tables("Fnameinfo").Rows(0)("IDEmp")
         name1.Text = Data.Tables("Fnameinfo").Rows(0)("EmpLastName")
         name2.Text = Data.Tables("Fnameinfo").Rows(0)("EmpNickName")
         positioning.Text = Data.Tables("Fnameinfo").Rows(0)("EmpPosition")
         duty.Text = Data.Tables("Fnameinfo").Rows(0)("EmpJob")
         Bdate.Text = Data.Tables("Fnameinfo").Rows(0)("EmpBeginDate")
         Money.Text = Data.Tables("Fnameinfo").Rows(0)("EmpSalary")
         StatusBox.Text = Data.Tables("Fnameinfo").Rows(0)("StatusEmp")
     Catch ex as Exception
	Messagebox.Show(ex.Message)
     End Try
   End Sub