选择列表框Winform控件中的所有项目 [英] Selecting all items in a ListBox Winform Control

问题描述

我正在尝试选择ListBox中的所有项目，并为此制定了这种扩展方法:

I'm trying to select all items in ListBox and made this extension method for this purpose:

    public static void SetSelectedAllItems(this ListBox ctl)
    {
        for (int i = 0; i < ctl.Items.Count; i++)
        {
            ctl.SetSelected(i, true);
        }
    }

问题是，如果列表框中有很多项目，则需要很长时间才能完成此任务，而且我可以看到列表框如何自动向下滚动并选择项目.

Problem is that if I have lots of items in the ListBox, it takes a long time to accomplish this task and I can watch how the ListBox is automatically scrolling down and selecting items.

是否有一种方法可以临时暂停控件的更新，以使任务更快地完成?我尝试使用:

Is there a way to temporary pause the update of a control, so that the task would finish faster? I tried using:

ctl.SuspendLayout();
  for (int i = 0; i < ctl.Items.Count; i++)
  ...
ctl.ResumeLayout();

但这似乎无济于事.

推荐答案

调用

Call the BeginUpdate and EndUpdate methods to prevent the drawing/rendering of the control while properties on that control are being set.

这是修改后的代码:

public static void SetSelectedAllItems(this ListBox ctl)
{
    ctl.BeginUpdate();

    for (int i = 0; i < ctl.Items.Count; i++)
    {
        ctl.SetSelected(i, true);
    }

    ctl.EndUpdate();
}

您说过，您曾尝试致电 SuspendLayout 和

You said that you've tried calling SuspendLayout and ResumeLayout, but that only affects the control's layout events. This pair of methods is used when you want to change a control's position relative to other controls, like when you set the Size, Location, Anchor, or Dock properties.

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