Visual Basic

Public Class MyControl
    Public Sub New
        SetStyle(ControlStyles.AllPaintingInWmPaint, True)
        SetStyle(ControlStyles.OptimizedDoubleBuffer, True)
        SetStyle(ControlStyles.UserPaint, True)
    End Sub

Protected Overrides Sub OnPaint(ByVal e As PaintEventArgs)
    Dim backBuffer As New Bitmap(Me.ClientRectangle.Width, Me.ClientRectangle.Height)
    Dim bg As Graphics = Graphics.FromImage(backBuffer)
    ' Do all your control painting here
    bg.draw...this and that
    bg.Dispose()
 
    ' Now draw your buffered image to your control surface
    Dim g As Graphics = e.Graphics
    g.DrawImage(backBuffer, 0, 0, backBuffer.Width, backBuffer.Height)
End Sub

    Dim sqlConn As SqlClient.SqlConnection<br />
    Dim command As SqlClient.SqlCommand<br />
    Dim adapter As SqlClient.SqlDataAdapter<br />
    Dim table As DataTable<br />
<br />
    Try<br />
      sqlConn = New SqlClient.SqlConnection("YOUR CONNECTION STRING")<br />
      command = New SqlClient.SqlCommand("OpersLogon", sqlConn)<br />
      With command<br />
        .Parameters.AddWithValue("@OperatorName", Server.HtmlEncode(logon1.UserName))<br />
        .Parameters.AddWithValue("@OperatorPassword", Server.HtmlEncode(logon1.Password))<br />
        .CommandType = CommandType.StoredProcedure<br />
      End With<br />
      adapter = New SqlClient.SqlDataAdapter(command)<br />
      table = New DataTable<br />
      adapter.Fill(table)<br />
      If CInt(table.Rows(0)(0)) <> 1 Then Throw New ApplicationException("Invalid User Credentials.")<br />
    Catch ex As Exception<br />
      ' Report or document the exception<br />
    Finally<br />
      If sqlConn.State <> ConnectionState.Closed Then sqlConn.Close()<br />
    End Try

Pete Newman wrote:

@ReturnValue INT OUTPUT

table = New DataTable<br />
adapter.Fill(table)<br />
If CInt(table.Rows(0)(0)) <> 1 Then

amapumu wrote:

How I can check if properties are Nothing dinamically (without knowing property type)?

When the propety "connected" (Boolean type) is nothing...

Private Function IsNull(ByRef obj As Object, ByVal prop As String) As Boolean
    Dim memberInfos() As MemberInfo = obj.GetType().GetMember(prop, BindingFlags.Instance Or BindingFlags.Public)
    If memberInfos.Length > 0 Then
        For Each mi As MemberInfo In memberInfos
            Debug.WriteLine(String.Format("Object Declaring Type: {0}", mi.DeclaringType.ToString()))
            Debug.WriteLine(String.Format("Object Reflected Type: {0}", mi.ReflectedType.ToString()))
            Debug.WriteLine(String.Format("    {0} is a {1}", mi.Name, mi.MemberType.ToString()))
            Select Case mi.MemberType
                Case MemberTypes.Property
                    Dim pi As PropertyInfo = obj.GetType().GetProperty(prop)
                    Dim v As Object = Nothing
                    v = pi.GetValue(obj, Nothing)
                    Debug.WriteLine(String.Format("    Value: {0} ({1})", v, pi.PropertyType().ToString()))
                    If v Is Nothing Then
                        Return True
                    Else
                        Return False
                    End If
            End Select
        Next
    Else
        Throw New InvalidArgumentException("Property name not found!")
    End If
End Function

PictureBox1.Image.Save(filepath)