"Use of an unassign local variable"-fejl

[System.Security.Permissions.PermissionSet(System.Security.Permissions.SecurityAction.Demand,
Name = "FullTrust")]
protected override void WndProc(ref Message Homeputer_Message)
{
  // Listen for operating system messages.
  if(Homeputer_Message.Msg == 3074)
  {
    // The WParam value identifies what is occurring,
    // objectID 0 is the clock therefore uninteresting.
    if (Homeputer_Message.WParam.ToInt32() != 0)
    {
      lbl_Windows_Handle_Info.Text +=
        "\nWP=" + Homeputer_Message.WParam.ToString() +
        " - " + DateTime.Now.ToString("hh:mm:ss");
     
      try
      {
        string ObjectName;
        string ObjectValue;
        Homeputer.homeputer_GetObjIdx(
          Homeputer_Message.WParam.ToInt32(),
          ref ObjectName,
          ref ObjectValue);
        lbl_Windows_Handle_Info.Text +=
          "\nObject Call Successful" +
          "\n Object Returned:" +
          "\n  Name:  " + ObjectName +
          "\n  Value: " + ObjectValue;
      }
      catch (SEHException e)
      {
        lbl_Windows_Handle_Info.Text += "\nObject calling error!";
        MessageBox.Show("Exception:\n" + e.ToString(),
          "External Calling Exception!");
      }
    }
    this.Invalidate();
  }
  base.WndProc(ref Homeputer_Message);
}