测试图片：
测试代码段：
1: //中文
2: public class InvisibleQueryConditionCollection : ControlCollection
3: {
4: public InvisibleQueryConditionCollection(Control owner)
5: : base(owner)
6: {
7: }
8:
9: public override void Add(Control child)
10: {
11: if (child is InvisibleQueryCondition)
12: {
13: base.Add(child);
14: }
15: }
16: }