vb.net ทำไมมันถึงติด error ตรงคำว่า checkstateconn() อะค่ะ

Option Explicit On
Option Strict On
Imports System.data
Imports system.data.sqlclient
Public Class frmUser
    Dim User As String = "Data Source=AUGSARA\SQL2005;Initial Catalog=myproject;Integrated Security=True;User ID=sa;Password=12345"
    Dim conn As New SqlConnection(User)
    Dim checkadd As DialogResult
    Private Sub frmUser_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
        show_dv1()
        Me.DataGridView1.Columns.Item(0).HeaderText = "เลือก"
        Me.DataGridView1.Columns.Item(1).HeaderText = "รหัสพนักงาน"
        Me.DataGridView1.Columns.Item(2).HeaderText = "ชื่อ-สกุล"
        Me.DataGridView1.Columns.Item(3).HeaderText = "ชื่อผู้ใช้"
        Me.DataGridView1.Columns.Item(4).HeaderText = "รหัสผ่าน"
        Me.DataGridView1.Columns.Item(0).Width = 40
        Me.DataGridView1.Columns.Item(1).Width = 100
        Me.DataGridView1.Columns.Item(2).Width = 200
        Me.DataGridView1.Columns.Item(3).Width = 100
        Me.DataGridView1.Columns.Item(4).Width = 100
        Me.cmdSearch.Enabled = True
        Me.cmdSave.Enabled = True
        Me.cmdEdit.Enabled = False
        Me.cmdDelete.Enabled = False
        Me.cmdClear.Enabled = False
    End Sub

    Sub show_dv1()
        If conn.State <> ConnectionState.Open Then
            conn.Open()
        End If
        Dim SQL As String
        SQL = "select*from tbUsers"
        Dim objDataAdapter1 As New SqlDataAdapter(SQL, conn)
        Dim objDataset1 As DataSet = New DataSet()
        objDataAdapter1.Fill(objDataset1, "xxxx")
        DataGridView1.DataSource = objDataset1
        DataGridView1.DataMember = "xxxx"
    End Sub

    Private Sub cmdSave_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles cmdSave.Click
        Dim checkadd As DialogResult
        If Me.txtEmp_No.Text = "" Then
            checkadd = MessageBox.Show("กรุณากรอกข้อมูลด้วยค่ะ", "เกิดข้อผิดพลาด", MessageBoxButtons.OK, MessageBoxIcon.Warning)
            If checkadd = Windows.Forms.DialogResult.OK Then
                Me.txtEmp_No.Focus()
            End If
        Else
            'CheckStateConn()
            Dim cmd As New SqlCommand("insert into tbUsers(Emp_No,Emp_name,txtUsername,txtPassword) values ('" & Me.Emp_No.Text & "','" & Me.Emp_name.Text & "','" & Me.txtUser_ID.Text & "','" & Me.txtPassword.Text & "')", conn)
            Try
                cmd.ExecuteNonQuery()
                MsgBox("การบันทึกข้อมูลเสร็จสมบูรณ์ ", MsgBoxStyle.Information, "การบันทึกข้อมูล ")
            Catch ex As Exception
                MsgBox("การบันทึกข้อมูลล้มเหลว!!", MsgBoxStyle.Critical, "การบันทึกข้อมูล")
            End Try
            Dim obdata As New SqlDataAdapter("select * from dbo.tblUsers", conn)
            Dim obdata1 As DataSet = New DataSet
            obdata.Fill(obdata1, "user")
            Me.DataGridView1.DataSource = obdata1
            Me.DataGridView1.DataMember = "user"
        End If
        clearAll()
        conn.Close()
        Me.txtEmp_No.Focus()
        show_dv1()
        Me.DataGridView1.Columns.Item(0).HeaderText = "เลือก"
        Me.DataGridView1.Columns.Item(1).HeaderText = "รหัสพนักงาน"
        Me.DataGridView1.Columns.Item(2).HeaderText = "ชื่อ-สกุล"
        Me.DataGridView1.Columns.Item(3).HeaderText = "ชื่อผู้ใช้"
        Me.DataGridView1.Columns.Item(4).HeaderText = "รหัสผ่าน"
        Me.DataGridView1.Columns.Item(0).Width = 40
        Me.DataGridView1.Columns.Item(1).Width = 100
        Me.DataGridView1.Columns.Item(2).Width = 200
        Me.DataGridView1.Columns.Item(3).Width = 100
        Me.DataGridView1.Columns.Item(4).Width = 100
        Me.cmdEdit.Enabled = True
        Me.cmdDelete.Enabled = True
        Me.cmdClear.Enabled = True
    End Sub
    Sub clearAll()
        Me.txtEmp_No.Text = ""
        Me.txtEmp_name.Text = ""
        Me.txtUser_ID.Text = ""
        Me.txtPassword.Text = ""
    End Sub
    Private Sub DataGridView1_CellContentClick(ByVal sender As System.Object, ByVal e As System.Windows.Forms.DataGridViewCellEventArgs) Handles DataGridView1.CellContentClick
        If e.RowIndex = e1 Then
        End If
        With DataGridView1
            Me.txtEmp_No.Text = .Rows.Item(e.RowIndex).Cells(1).Value.ToString()
            Me.txtEmp_name.Text = .Rows.Item(e.RowIndex).Cells(2).Value.ToString()
            Me.txtUser_ID.Text = .Rows.Item(e.RowIndex).Cells(3).Value.ToString()
            Me.txtPassword.Text = .Rows.Item(e.RowIndex).Cells(4).Value.ToString()
        End With
    End Sub

    Private Sub cmdClear_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles cmdClear.Click
        clearAll()
        Me.txtEmp_No.Focus()
    End Sub

    Private Sub cmdDelete_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles cmdDelete.Click
        Dim checkadd As DialogResult
        If Me.txtEmp_No.Text = "" Then checkadd = MessageBox.Show("กรุณาเลือกข้อมูลที่ต้องการลบ", "เกิดข้อผิดพลาด", MessageBoxButtons.OK, MessageBoxIcon.Warning)
        If checkadd = Windows.Forms.DialogResult.OK Then
            Me.txtEmp_No.Focus()
        Else
             CheckStateConn()
            Dim Result As DialogResult
            Result = MessageBox.Show("คุณต้องการลบข้อมูลใช่หรือไม่?", "ยืนยันการลบข้อมูล", MessageBoxButtons.YesNo, MessageBoxIcon.Information)
            If Result = Windows.Forms.DialogResult.Yes Then
                Dim cmd As New SqlCommand("delete from tbUsers where Emp_No= '" & Me.txtEmp_No.Text & "'", conn)
                cmd.ExecuteNonQuery()
            End If
        End If
        Try
        Catch ex As Exception
            MsgBox("การลบข้อมูลล้มเหลว!!", MsgBoxStyle.Critical, "การลบข้อมูล")
        End Try
        Dim obdata As New SqlDataAdapter("select * from dbo.tbLUsers", conn)
        Dim obdata1 As DataSet = New DataSet
        obdata.Fill(obdata1, "user")
        Me.DataGridView1.DataSource = obdata1
        Me.DataGridView1.DataMember = "user"
        Me.txtEmp_No.Text = ""
        Me.txtEmp_name.Text = ""
        Me.txtUser_ID.Text = ""
        Me.txtPassword.Text = ""
        conn.Close()
        Me.txtEmp_No.Focus()
        show_dv1()
        show_dv1()
        Me.DataGridView1.Columns.Item(0).HeaderText = "เลือก"
        Me.DataGridView1.Columns.Item(1).HeaderText = "รหัสพนักงาน"
        Me.DataGridView1.Columns.Item(2).HeaderText = "ชื่อ-สกุล"
        Me.DataGridView1.Columns.Item(3).HeaderText = "ชื่อผู้ใช้"
        Me.DataGridView1.Columns.Item(4).HeaderText = "รหัสผ่าน"
        Me.DataGridView1.Columns.Item(0).Width = 40
        Me.DataGridView1.Columns.Item(1).Width = 100
        Me.DataGridView1.Columns.Item(2).Width = 200
        Me.DataGridView1.Columns.Item(3).Width = 100
        Me.DataGridView1.Columns.Item(4).Width = 100
    End Sub

    Private Sub cmdEdit_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles cmdEdit.Click
        Dim checkadd As DialogResult
        If Me.txtEmp_No.Text = "" Then
            checkadd = MessageBox.Show("กรุณาเลือกข้อมูลที่ต้องการแก้ไข", "เกิดข้อผิดพลาด", MessageBoxButtons.OK, MessageBoxIcon.Warning)
            If checkadd = Windows.Forms.DialogResult.OK Then
                Me.txtEmp_No.Focus()
            End If
        Else
            'CheckStateConn()
            Dim update As SqlCommand = New SqlCommand("UPDATE tbUsers SET Emp_name='" & Me.txtEmp_name.Text & "',txtUser_ID='" & Me.txtUser_ID.Text & "',txtPassword='" & Me.txtPassword.Text & "' WHERE Emp_No='" & Me.txtEmp_No.Text & "'", conn)
            Try
                update.ExecuteNonQuery()
                MessageBox.Show("แก้ไขข้อมูลเรียบร้อย", "ผลการแก้ไข", MessageBoxButtons.OK, MessageBoxIcon.Asterisk)
            Catch ex As Exception
                MessageBox.Show("การแก้ไขข้อมูลผิดพลาด!!", "ผลการแก้ไข", MessageBoxButtons.OK, MessageBoxIcon.Error)
            End Try
        End If
        Dim obdata As New SqlDataAdapter("select * from dbo.tblUsers", conn)
        Dim obdata1 As DataSet = New DataSet()
        obdata.Fill(obdata1, "user")
        Me.DataGridView1.DataSource = obdata1
        Me.DataGridView1.DataMember = "user"
        Me.txtEmp_No.Text = ""
        Me.txtEmp_name.Text = ""
        Me.txtUser_ID.Text = ""
        Me.txtPassword.Text = ""
        conn.Close()
        Me.txtEmp_No.Focus()
        show_dv1()
        show_dv1()
        Me.DataGridView1.Columns.Item(0).HeaderText = "เลือก"
        Me.DataGridView1.Columns.Item(1).HeaderText = "รหัสพนักงาน"
        Me.DataGridView1.Columns.Item(2).HeaderText = "ชื่อ-สกุล"
        Me.DataGridView1.Columns.Item(3).HeaderText = "ชื่อผู้ใช้"
        Me.DataGridView1.Columns.Item(4).HeaderText = "รหัสผ่าน"
        Me.DataGridView1.Columns.Item(0).Width = 40
        Me.DataGridView1.Columns.Item(1).Width = 100
        Me.DataGridView1.Columns.Item(2).Width = 200
        Me.DataGridView1.Columns.Item(3).Width = 100
        Me.DataGridView1.Columns.Item(4).Width = 100
    End Sub
    Sub DisplayData() 'Refresh ข้อมูลในตาราง
        Dim objdataadapter As New SqlDataAdapter("select Emp_No,Emp_name,txtUsername,txtPassword from tbUsers where Emp_No ='" & Me.txtEmp_No.Text & "'", conn)
        Dim objdataset As New DataSet
        'CheckStateConn()
        objdataadapter.Fill(objdataset, "user") 'ชื่อนี้แล้วแต่จะตั้งไม่เกี่ยวกับชื่อของดาต้าเบส
        DataGridView1.DataSource = objdataset
        DataGridView1.DataMember = "user" 'ชื่อนี้ตั้งเหมือนกันกับดาต้าเบส ที่กำหนดไว้่
    End Sub

    Private Sub cmdSearch_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles cmdSearch.Click
        If Me.txtEmp_No.Text = "" Then MessageBox.Show("กรุณากรอกรหัสพนักงาน", "คำเตือน", MessageBoxButtons.OK, MessageBoxIcon.Warning)
        'CheckStateConn()
        Dim objDataAdapter1 As New SqlDataAdapter("select Emp_No,Emp_name,txtUsername,txtPassword from tbUsers where Emp_No ='" & Me.txtEmp_No.Text & "'", conn)
        Dim objdataset1 As DataSet = New DataSet()
        'CheckStateConn()
        objDataAdapter1.Fill(objdataset1, "user")
        DataGridView1.DataSource = objdataset1
        DataGridView1.DataMember = "user"
        Me.DataGridView1.Columns.Item(0).HeaderText = "เลือก"
        Me.DataGridView1.Columns.Item(1).HeaderText = "รหัสพนักงาน"
        Me.DataGridView1.Columns.Item(2).HeaderText = "ชื่อ-สกุล"
        Me.DataGridView1.Columns.Item(3).HeaderText = "ชื่อผู้ใช้"
        Me.DataGridView1.Columns.Item(4).HeaderText = "รหัสผ่าน"
        Me.DataGridView1.Columns.Item(0).Width = 40
        Me.DataGridView1.Columns.Item(1).Width = 100
        Me.DataGridView1.Columns.Item(2).Width = 200
        Me.DataGridView1.Columns.Item(3).Width = 100
        Me.DataGridView1.Columns.Item(4).Width = 100
        Me.cmdEdit.Enabled = True
        Me.cmdDelete.Enabled = True
        Me.cmdClear.Enabled = True
    End Sub
    Private Sub TextBox1_KeyUp(ByVal sender As Object, ByVal e As System.Windows.Forms.KeyEventArgs) Handles Emp_No.KeyUp
        If e.KeyCode = Keys.Enter Then
            Me.cmdSearch_Click(sender, e)
        End If
    End Sub
End Class