InforPath的几个基础性的东西

1.MainDataSource

 获取表单的数据源

 下面这段代码是检查filed1不为空，若为空，则提示（需添加引用，system.windows.forms）

2. this.NameSpaceManager

NameSpace: Microsoft.Office.InfoPath

 XPathNavigator text1 = MainDataSource.CreateNavigator().SelectSingleNode("/my:myFields/my:field1",this.NamespaceManager);
            if (string.IsNullOrEmpty(text1.Value))
            {
                MessageBox.Show("This field Cannot be null !");
            }

            XPathNavigator tex2 = MainDataSource.CreateNavigator().SelectSingleNode("/my:myFields/my:field2", this.NamespaceManager);
            tex2.SetValue("I just get the value");