อยากทราบว่า ทำไมตอนที่เราเพิ่มข้อมูลในหน้าฟอล์มแล้วมันเพิ่มได้ แต่ในฐานข้อมูลมันไม่บันทึกข้อมูลที่เราเพิ่มจากหน้าฟอล์มคับ

Imports System.Data
Imports System.Data.SqlClient

Public Class FrmCategory

    Private Sub UpdateBinding()
        TextID.DataBindings.Clear()
        TextName.DataBindings.Clear()


        sql = "SELECT * FROM Categories"
        command = New SqlCommand(sql, connection)
        adapter = New SqlDataAdapter(command)
        dataSt = New DataSet()
        adapter.Fill(dataSt, "category")

        bindingSrc = New BindingSource()
        bindingSrc.DataSource = dataSt.Tables("category")

        TextID.DataBindings.Add("Text", bindingSrc, "CategoryID")
        TextName.DataBindings.Add("Text", bindingSrc, "CategoryName")

        ListBox1.DataSource = dataSt.Tables("category")
        ListBox1.DisplayMember = "CategoryName"


    End Sub

    Private Sub FrmCategory_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
        connection = New SqlConnection(conStr)
        If connection.State = ConnectionState.Closed Then
            connection.Open()
        End If

        UpdateBinding()
        BtnSave.Enabled = False
    End Sub

    Private Sub ListBox1_SelectedIndexChanged() _
     Handles ListBox1.SelectedIndexChanged
        If (bindingSrc Is Nothing) Then
            Exit Sub
        End If
        bindingSrc.Position = ListBox1.SelectedIndex
        Toolstriplabel1.Text = _
        "ลำดับที่: " & (bindingSrc.Position + 1) & "/" & bindingSrc.Count

        ShowDetails()
    End Sub

    Private Sub ShowDetails()
        If Not (dataSt.Tables("product") Is Nothing) Then
            dataSt.Tables("product").Clear()
        End If

        sql = "SELECT ProductID,ProductName,UnitPrice FROM Product "

        command.CommandText = sql
        adapter.SelectCommand = command
        adapter.Fill(dataSt, "product")
        DataGridView1.DataSource = dataSt.Tables("product")

        Dim headerText() As String = {"รหัสสินค้า", "ชื่อสินค้า", "ราคาขาย"}

        For i = 0 To headerText.Count - 1
            DataGridView1.Columns(i).HeaderText = headerText(i)

        Next


    End Sub

    Private Sub BtnAdd_Click() _
    Handles BtnAdd.Click
        If BtnAdd.Text = "เพิ่มข้อมูล" Then
            BtnAdd.Text = "ยกเลิก"
            BtnSave.Enabled = True
            ListBox1.Enabled = False
            TextID.Text = ""
            TextName.Text = ""
        Else
            BtnAdd.Text = "เพิ่มข้อมูล"
            BtnSave.Enabled = False
            ListBox1.Enabled = True
            UpdateBinding()

        End If
    End Sub

    Private Sub BtnSave_Click() Handles BtnSave.Click
        If IsDataComplete() = False Then
            Exit Sub
        End If
        sql = " INSERT INTO Categories(CategoryName)VALUES(@name)"
        command.Parameters.Clear()
        command.CommandText = sql
        command.Parameters.AddWithValue("name", TextName.Text)


        Dim result As Integer = command.ExecuteNonQuery()
        If result = -1 Then
            MessageBox.Show("เกิดข้อผิดพลาดไม่สามารถเพิ่มข้อมูลได้")
        Else
            MessageBox.Show("บันทึกข้อมูลแล้ว")
            BtnAdd.PerformClick()

        End If
    End Sub
    Private Function IsDataComplete() As Boolean
        TextName.Text.Trim()
        If TextName.Text = "" Then
            MessageBox.Show("กรุณาใส่ข้อมูลให้ครบ")
            Return False
        Else
            Return True

        End If
    End Function

    Private Sub BtnEdit_Click() Handles BtnEdit.Click
        If TextID.Text = "" Or IsDataComplete() = False Then
            Exit Sub
        End If

        sql = "UPDATE Categories SET  CategoryName = @name WHERE CategoryID = @id"

        command.Parameters.Clear()
        command.CommandText = sql
        command.Parameters.AddWithValue("name", TextName.Text)
        command.Parameters.AddWithValue("id", TextID.Text)

        If command.ExecuteNonQuery() = 1 Then
            MessageBox.Show("บันทึกการเปลี่ยนแล้ว")
            UpdateBinding()
        Else
            MessageBox.Show("เกิดข้อพลาดในการแก้ไขข้อมูล")
        End If

    End Sub

    Private Sub BtnDelete_Click() Handles BtnDelete.Click
        If TextID.Text = "" Then
            Exit Sub
        End If

        Dim result As DialogResult = _
        MessageBox.Show("ท่านต้องการลบข้อมูลแถวนี้จริงหรือไม่", "ยืนยันการลบ", MessageBoxButtons.OKCancel)
        If result = DialogResult.Cancel Then
            Exit Sub
        End If

        sql = "DELETE FROM Categories WHERE CategoryID = " & TextID.Text
        command.Parameters.Clear()
        command.CommandText = sql
        command.ExecuteNonQuery()

        UpdateBinding()
    End Sub

End Class