ListView在C#.net中单击listview的空白时失去焦点 [英] ListView Losing focus while clicking on blank space of listview in C#.net

问题描述

大家好，
我有一个列表视图.显示其项目，并单击每个项目都没有问题.但是，当该列表视图停靠(填充)到面板中时.当我单击列表视图的空白区域时(我相信)，我的意思是该列表视图在该面板中的空白行.我当前的selectedItem将更改为false.我不知道单击列表视图的空白区域的事件处理.那我可以禁用它...


预先感谢.

Hi all,
I have a listview. Its items are displayed and click on each item is not a problem. But while that listview is docked (fill) into a panel. When I click on an empty area of a listview (I believe), I means an empty row of that listview in that panel. My current selectedItem will be changed to false. I dont know what event handle that click at an empty area of a listview. Then I can disable it...


Thanks in advance.

推荐答案

嗨阿普尔瓦，

这是一种可能的解决方案:忽略在ListView的客户端区域中单击鼠标的操作.

Hi Apurva,

This is one possible solution for this: Ignore the mouse-click in the client area of the ListView.

using System;
using System.Windows.Forms;
using System.Drawing;
namespace ListViewFocusDemo
{
    static class Program
    {
        class MyListView : ListView        
        {
            protected override void WndProc(ref Message msg)
            {
                // Ignore mouse messages not in the client area 
                if (msg.Msg >= 0x201 && msg.Msg <= 0x209)
                {
                    Point pointMousePos = new Point(msg.LParam.ToInt32() & 0xffff, msg.LParam.ToInt32() >> 16);
                    ListViewHitTestInfo lvhti = this.HitTest(pointMousePos);
                    switch (lvhti.Location)
                    {
                        case ListViewHitTestLocations.AboveClientArea:
                        case ListViewHitTestLocations.BelowClientArea:
                        case ListViewHitTestLocations.LeftOfClientArea:
                        case ListViewHitTestLocations.RightOfClientArea:
                        case ListViewHitTestLocations.None:
                            return;
                    }
                }
                base.WndProc(ref msg);
            }
        }
        static void Main()
        {
            // Create a ListView
            MyListView listview = new MyListView();
            listview.Dock = DockStyle.Fill;
            listview.View = View.Details;
            listview.CausesValidation = false;
            // ... add some columns
            listview.Columns.Add("Name");
            listview.Columns.Add("Value");
            // ... and dummy items
            listview.Items.Add(new ListViewItem(new string[] { "IsListView", "Yes" }));
            listview.Items.Add(new ListViewItem(new string[] { "IsDoingWhatIWant", "No"}));
            Label label = new Label();
            label.Dock = DockStyle.Bottom;
            listview.SelectedIndexChanged += delegate(object obj, EventArgs ea)
            {
                label.Text = String.Format("Selected Index = {0}",
                    listview.SelectedIndices.Count > 0 ? listview.SelectedIndices[0] : -1);
            };
           
            // Create a Test-Form
            Form form = new Form();           
            form.Controls.Add(listview);
            form.Controls.Add(label);
            Application.Run(form);
        }
    }
}

另一个解决方案是，如果发生取消选择(SelectedIndexChanged，ItemSelectionChanged)，则重新创建选择.

Another solution would be to recreate the selection if the unselection occurs (SelectedIndexChanged, ItemSelectionChanged).

listView1_SelectedIndeChaned(object sender, EventArgs e)
   {
   try
   {
        // your code here
   }
   catch
   {
        // leave empty to catch error
   }
}

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