基线对齐线在自定义的WinForms控件 [英] Baseline snaplines in custom Winforms controls

问题描述

我上有一个文本框自定义用户控件，我想公开（文本框中的文本）的基线对齐线的自定义控制范围之外。我知道你创建一个设计师（自ControlDesigner继承），并覆盖对齐线来获得访问对齐线，但我不知道怎么弄，我已经通过我的自定义用户控件曝光控制的文本基线。

I have a custom user control with a textbox on it and I'd like to expose the baseline (of the text in the textbox) snapline outside of the custom control. I know that you create a designer (inherited from ControlDesigner) and override SnapLines to get access to the snaplines, but I'm wondering how to get the text baseline of a control that I have exposed by my custom user control.

推荐答案

我也有类似的需求，我解决了它是这样的：

I just had a similar need, and I solved it like this:

 public override IList SnapLines
{
    get
    {
        IList snapLines = base.SnapLines;

        MyControl control = Control as MyControl;
        if (control == null) { return snapLines; }

        IDesigner designer = TypeDescriptor.CreateDesigner(
            control.textBoxValue, typeof(IDesigner));
        if (designer == null) { return snapLines; }
        designer.Initialize(control.textBoxValue);

        using (designer)
        {
            ControlDesigner boxDesigner = designer as ControlDesigner;
            if (boxDesigner == null) { return snapLines; }

            foreach (SnapLine line in boxDesigner.SnapLines)
            {
                if (line.SnapLineType == SnapLineType.Baseline)
                {
                    snapLines.Add(new SnapLine(SnapLineType.Baseline,
                        line.Offset + control.textBoxValue.Top,
                        line.Filter, line.Priority));
                    break;
                }
            }
        }

        return snapLines;
    }
}

此方式，它实际上是建立一个临时的子设计的子控件，以便找出真正的基准线弹线就是。

This way it's actually creating a temporary sub-designer for the subcontrol in order to find out where the "real" baseline snapline is.

这似乎在测试高性能合理的，但如果PERF成为一个问题（如果内部文本框不动），那么这个最code可以提取到初始化方法。

This seemed reasonably performant in testing, but if perf becomes a concern (and if the internal textbox doesn't move) then most of this code can be extracted to the Initialize method.

这还假定该文本框的用户控件的直接子。如果存在方式与其它布局影响控制则偏移计算变得更加复杂。

This also assumes that the textbox is a direct child of the UserControl. If there are other layout-affecting controls in the way then the offset calculation becomes a bit more complicated.

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