ช่วยด้วยคร๊าบ!!! เพิ่มข้อมูลเข้า SQL แล้วติดตรง Mycommand.Parameters.Clear()

Imports System.Data
Imports System.Data.SqlClient
Public Class frmDevice
    Private Mycommand As SqlCommand
    Private dataSt As DataSet
    Private adapter As SqlDataAdapter
    Private bindingSrc As BindingSource
    Private sql As String
    Private Sub frmDevice_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
        Dim conStr As String = "Data Source=.\SQLEXPRESS;" &
        "AttachDbFilename=|DataDirectory|\iConWorkDATA.mdf" &
        "Integrated Security=True;User Instance=True"
        Dim connection As SqlConnection
        connection = New SqlConnection(conStr)
    End Sub
    Private Sub btnExit_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnExit.Click
        Me.Close()
    End Sub

    Private Sub btnSaveAdd_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnSaveAdd.Click
        If IsDataComplete() = False Then
            Exit Sub
        End If
        sql = "INSERT INTO Device"
        sql = "(DeID, DeAsset, DeDv, Brand, Model, SnNo, WarY, EndWar, WarSub, Detail)"
        sql = "VALUES(@devid, @devdv, @devbrand, @devmodel, @devsn, @devwary, @devendW, @devwars, @devdet"
        AddParameters(sql)
        Dim r As Integer = Mycommand.ExecuteNonQuery()
        If r > 0 Then
            MessageBox.Show("บันทึกข้อมูลเรียบร้อยแล้ว")
            btnSaveAdd.PerformClick()
        Else
            MessageBox.Show("เกิดข้อผิดพลาดในการบันทึกข้อมูล")
        End If
    End Sub
    Private Sub AddParameters(ByVal sql As String)
        Mycommand.Parameters.Clear() <<<<<<<<<<<<<<<<<<<<<<< ติดบรรทัดนี้
        Mycommand.CommandText = sql
        Mycommand.Parameters.AddWithValue("DeID", txtDevID.Text)
        Mycommand.Parameters.AddWithValue("DeAsset", txtDevAsset.Text)
        Mycommand.Parameters.AddWithValue("DeDv", txtDev.Text)
        Mycommand.Parameters.AddWithValue("Brand", txtDevBrand.Text)
        Mycommand.Parameters.AddWithValue("Model", txtDevModel.Text)
        Mycommand.Parameters.AddWithValue("SnNo", txtDevSn.Text)
        Mycommand.Parameters.AddWithValue("WarY", txtWarr.Text)

        Dim dateStr As String = dtpDevWarDate.Value.Year
        dateStr &= "/" & dtpDevWarDate.Value.Month
        dateStr &= "/" & dtpDevWarDate.Value.Day

        Mycommand.Parameters.AddWithValue("EndWar", dateStr)
        Mycommand.Parameters.AddWithValue("WarSub", txtDevSub.Text)
        Mycommand.Parameters.AddWithValue("Detail", txtDevDetail.Text)
    End Sub
    Private Function IsDataComplete() As Boolean
        txtDevID.Text.Trim()
        txtDev.Text.Trim()
        txtDevBrand.Text.Trim()
        txtDevModel.Text.Trim()
        Dim errMsg As String = ""
        If txtDevID.Text = "" Then
            errMsg = "ยังไม่ได้ระบุรหัสเครื่อง"
        ElseIf txtDev.Text = "" Then
            errMsg = "ยังไม่ได้ระบุประเภทอุปกรณ์"
        ElseIf txtDevBrand.Text = "" Then
            errMsg = "ยังไม่ได้ระบุยี่ห้ออุปกรณ์"
        ElseIf txtDevModel.Text = "" Then
            errMsg = "ยังไม่ได้รุ่นของอุปกรณ์"
        End If
        If errMsg <> "" Then
            MessageBox.Show(errMsg)
            Return False
        Else
            Return True
        End If
    End Function
End Class