Question

我正在使用ListView类的事件ItemSelectionChanged和SelectedIndexChanged来回答this question。

下面的代码是，似乎唯一存在的错误是，当用户使用橡皮筋选择时，不仅是单击选择还是双击选择，我还使用250ms计时器。

internal Form1()
{
    InitializeComponent();

    t.Tick += T_Tick;
}

internal bool santinela = false;

internal void T_Tick(object sender, EventArgs e)
{
    t.Stop();

    if (!santinela)
    {
        bool newVal = selectionChangedItem.Selected;

        selectionChangedItem.Checked =
            selectionChangedItem.Selected = newVal;

        santinela = true;
    }
}

internal Timer t = new Timer()
{
    Interval = 250
};

internal bool santinela3 = true;

internal void listView1_ItemCheck(object sender, ItemCheckEventArgs e)
{
    if (santinela3)
    {
        if (e.CurrentValue == CheckState.Checked)
        {
            listView1.SelectedIndices.Remove(e.Index);
        }
        else if (e.CurrentValue == CheckState.Unchecked)
        {
            listView1.SelectedIndices.Add(e.Index);
        }
    }
}

internal void listView1_ItemActivate(object sender, EventArgs e)
{
    if (listView1.SelectedItems.Count > 0)
    {
        MessageBox.Show(listView1.SelectedItems[0].Text);
    }
}

internal ListViewItem selectionChangedItem = null;

internal bool santinela2 = true;

internal void listView1_ItemSelectionChanged(object sender, ListViewItemSelectionChangedEventArgs e)
{
    if (!santinela2)
    {
        return;
    }

    if (t.Enabled)
    {
        santinela = true;

        t.Stop();

        // double click: both clicks must be done in the same place
        if (e.Item == selectionChangedItem)
        {
            if (!e.IsSelected)
            {
                santinela2 = true;

                e.Item.Selected = true;

                santinela2 = false;
            }

            listView1_ItemActivate(sender, EventArgs.Empty);
        }

        selectionChangedItem = null;
    }
    else
    {
        santinela = false;

        t.Stop();

        selectionChangedItem = e.Item;

        t.Start();
    }
}

internal void listView1_SelectedIndexChanged(object sender, EventArgs e)
{
    if (listView1.SelectedIndices.Count == 0)
    {
        santinela = true;

        t.Stop();

        selectionChangedItem = null;


        santinela3 = false;
        for (int i = 0; i < listView1.CheckedItems.Count; ++i)
        {
            listView1.CheckedItems[i].Checked = false;
        }
        santinela3 = true;
    }
}

相关的设计师代码如下：

System.Windows.Forms.ListViewItem listViewItem1 = new System.Windows.Forms.ListViewItem("item1");
System.Windows.Forms.ListViewItem listViewItem2 = new System.Windows.Forms.ListViewItem("item2");
this.listView1 = new System.Windows.Forms.ListView();
this.SuspendLayout();
// 
// listView1
// 
this.listView1.CheckBoxes = true;
listViewItem1.StateImageIndex = 0;
listViewItem2.StateImageIndex = 0;
this.listView1.Items.AddRange(new System.Windows.Forms.ListViewItem[] {
listViewItem1,
listViewItem2});
this.listView1.Location = new System.Drawing.Point(12, 12);
this.listView1.Name = "listView1";
this.listView1.Size = new System.Drawing.Size(401, 327);
this.listView1.TabIndex = 0;
this.listView1.UseCompatibleStateImageBehavior = false;
this.listView1.ItemActivate += new System.EventHandler(this.listView1_ItemActivate);
this.listView1.ItemCheck += new System.Windows.Forms.ItemCheckEventHandler(this.listView1_ItemCheck);
this.listView1.ItemSelectionChanged += new System.Windows.Forms.ListViewItemSelectionChangedEventHandler(this.listView1_ItemSelectionChanged);
this.listView1.SelectedIndexChanged += new System.EventHandler(this.listView1_SelectedIndexChanged);

更新：由于计时器问题，我面临的问题是，在用橡皮筋将ListViewItem悬停后，在检查项目之前存在计时器无用的延迟。当用户调整橡皮筋的大小/移动橡皮筋以便不再检查ListViewItem时，会有相同的延迟。如果用户不知道该非标准延迟，则选择可能是错误的。

如何在ListView的橡皮筋选择中找到选择？

0 个答案: