Private Sub FrmStudent_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
        OleDbConnection1.ConnectionString = strCon
        Refresh_Form()
 
    End Sub
 
Module ModuleConnection
    Public Con As System.Data.OleDb.OleDbConnection
    Public U, P, S, D, strCon As String
    Public ObjCon As FrmConnection
    Public Sub prcConnect(ByVal U, ByVal P, ByVal S, ByVal D)
        Try
            strCon = "provider=SQLOLEDB;User id=" & U & ";Password=" & P & ";Server=" & S & ";database=" & D
            Con = New System.Data.OleDb.OleDbConnection(strCon)
            Con.Open()
            MsgBox("Connection to the Database is Successful", MsgBoxStyle.Information, "Welcome")
        Catch ex As Exception
            MsgBox(ex.Message, MsgBoxStyle.Exclamation, "Error Connecting To Database")
            ObjCon = New FrmConnection
            ObjCon.Show()
        End Try
    End Sub
 
End Module

Private Sub cmdSave_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles cmdSave.Click
 
        If Len(Trim(txtstudCd.Text)) = 0 Then
            MessageBox.Show("Please Student Id cannot be blank", "Input Error", MessageBoxButtons.OK, MessageBoxIcon.Error)
            Exit Sub
        End If
        If Len(Trim(txtFirstName.Text)) = 0 Then
            MsgBox("Please FirstName cannot be blank", MsgBoxStyle.OkOnly, "Enter Name")
            Exit Sub
        End If
        If Len(Trim(txtLastName.Text)) = 0 Then
            MsgBox("Please LastName cannot be blank", MsgBoxStyle.OkOnly, "Enter Name")
            Exit Sub
        End If
 
        If Not IsNumeric(txtAge.Text) Then
            MessageBox.Show("Please Age must be Numeric value", "Input Error", MessageBoxButtons.OK, MessageBoxIcon.Error)
            txtAge.Text = ""
            txtAge.Focus()
            Exit Sub
        End If
 
        If Not IsNumeric(txtstudCd.Text) Then
            MessageBox.Show("Please Student Id must be Numeric Value", "Input Error", MessageBoxButtons.OK, MessageBoxIcon.Error)
            txtstudCd.Text = ""
            txtstudCd.Focus()
 
        End If
 
 
        Dim Con As New OleDb.OleDbConnection(strCon)
        Dim strSQL As String = _
        "INSERT INTO Student (StudentCode, FirstName, LastName, Age)" & _
        " VALUES(@StudentCode, @FirstName, @LastName, @Age )"
 
        Dim cmd As New OleDb.OleDbCommand(strCon)
        With cmd
            .Parameters.Add(New OleDb.OleDbParameter("@StudentCode", SqlDbType.NVarChar, 6)).Value = txtstudCd.Text
            .Parameters.Add(New OleDb.OleDbParameter("@FirstName", SqlDbType.NVarChar, 30)).Value = txtFirstName.Text
            .Parameters.Add(New OleDb.OleDbParameter("@LastName", SqlDbType.NVarChar, 30)).Value = txtLastName.Text
            .Parameters.Add(New OleDb.OleDbParameter("@Age", SqlDbType.NVarChar, 3)).Value = txtAge.Text
        End With
        Con.Open()
        cmd.ExecuteNonQuery()
        Con.Close()
        MsgBox("Data Saved", MsgBoxStyle.Information, "Hello")
        Refresh_Form()
 
End Sub

Try
  strCon = "provider=SQLOLEDB;User id=" & U & ";Password=" & P & ";Server=" & S & ";database=" & D
  Con = New System.Data.OleDb.OleDbConnection(strCon)
  Con.Open()
  MsgBox("Connection to the Database is Successful", MsgBoxStyle.Information, "Welcome")
Catch ex As Exception
  MsgBox(ex.Message, MsgBoxStyle.Exclamation, "Error Connecting To Database")
  ObjCon = New FrmConnection
  ObjCon.Show()
Finally
  If Con IsNot Nothing AndAlso Con.State = ConnectionState.Open Then
    Con.Close()
  End If
End Try

Try
  Con.Open()
  cmd.ExecuteNonQuery()
  Con.Close()
  ' Success
Catch ex As Exception
  ' Handle error
End try

Try
            strCon = "provider=SQLOLEDB;User id=" & U & ";Password=" & P & ";Server=" & S & ";database=" & D
            Con = New System.Data.OleDb.OleDbConnection(strCon)
            Con.Open()
 
            'EXECUTE YOUR COMMAND HERE
            Dim strSQL As String = _
        "INSERT INTO Student (StudentCode, FirstName, LastName, Age)" & _
        " VALUES(@StudentCode, @FirstName, @LastName, @Age )"
 
            Dim cmd As New OleDb.OleDbCommand(Con)
            With cmd
                .Parameters.AddWithValue("@StudentCode", txtstudCd.Text)
                .Parameters.AddWithValue("@FirstName", txtFirstName.Text)
                .Parameters.AddWithValue("@LastName", txtLastName.Text)
                .Parameters.AddWithValue("@Age" txtAge.Text)
            End With
            cmd.ExecuteNonQuery()
 
 
        Catch ex As Exception
            MsgBox(ex.Message, MsgBoxStyle.Exclamation, "Error Connecting To Database")
 
        Finally
            If Con IsNot Nothing AndAlso Con.State = ConnectionState.Open Then
                Con.Close() 
                'cleanup 
                Con.Dispose
                Con = Nothing
                cmd = nothing
            End If
        End Try