问题描述
我认为可以通过 .Owner 属性或通过在重载方法 ShowDialog(IWin32Window owner)
I presume a winform's owner can be set explicitly via the .Owner property OR by passing the owner in the overloaded method ShowDialog(IWin32Window owner)
我无法理解为什么这些方法在处理 MDI 表单时会表现出不同的行为.
I am unable to understand why these methods exhibit different behavior when working with MDI forms.
我创建了一个 MDIParent 和一个 MDIChild.
I have created an MDIParent and an MDIChild.
我还有一个简单的 winform MyDialogBox，它在加载时显示其所有者.
I also have a simple winform MyDialogBox that displays its owner on load.
MessageBox.Show("Dialog's owner is " + this.Owner.Name);
方法 A - 在加载 MDIChild 我有以下代码，这导致 MyDialogBox 的所有者被设置为 MDIChild
Method A - In the load of MDIChild I have the following code, which causes the MyDialogBox's owner to be set to MDIChild
MyDialogBox box = new MyDialogBox();
box.Owner = this; // Set owner as MDIChild
box.ShowDialog();
方法 B - 或者，在 MDIChild 的加载方法中，我有以下代码，这导致 MyDialogBox 的所有者被设置为 MDIParent
Method B - Alternatively, in the load method of MDIChild I have the following code, which causes the MyDialogBox's owner to be set to MDIParent
MyDialogBox box = new MyDialogBox();
box.ShowDialog(this); // Pass MyMDIChild as owner
我还阅读了以下这里
只有 MDI 父窗体可以拥有另一个窗体，无论是 MDI 子窗体、模式对话框还是父窗体设置为所有者参数的窗体.
如果是这样，方法 A 根本不应该工作，不是吗?
If so Method A should not work at all, isn't it ?
我错过了什么?为什么方法 B 不将所有者设置为 MDIChild ?
What am I missing? Why doesn't method B set the owner to MDIChild ?
推荐答案
看这2个选项使用Reflector的区别，似乎它们的实现略有不同:box.Owner = this 只需将提供的 this 值分配给内部所有者字段.但是，当调用 ShowDialog(IWin32Window) 时，实现会在分配值之前执行以下调用:
Looking at the differences of these 2 options using Reflector, it seems that they have a slightly different implementation:
box.Owner = this just assign the provided value of this to the internal owner field.
However, when calling ShowDialog(IWin32Window), the implementation performs the following call, prior to assigning the value:
owner = ((Control) owner).TopLevelControlInternal;
这可能会导致分配 MDIParent.
This might result in assignment of the MDIParent.
(注意:我远不是 MDI 方面的专家，所以我在这里可能错了).
(Note: I'm far from being an expert regarding MDI, so I might be wrong here).
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