Welcome to OGeek Q&A Community for programmer and developer-Open, Learning and Share
Welcome To Ask or Share your Answers For Others

Categories

0 votes
583 views
in Technique[技术] by (71.8m points)

c# - How to change default selection color of a ListView?

I'm trying to change the default (blue) color of selection bar in ListView.
I'm refusing to use ObjectListView since I'll have to change all the code.

I've searched on this subject and found some answers here:
Change background selection color of ListView?
but that points to ObjectListView.

When I was using ListBox before, this worked to set the selection bar color to my likings:

  1. Set DrawMode to OwnerDrawFixed under Properties
  2. Set DrawItem to ListBox1_DrawItem under Events

private void ListBox1_DrawItem(object sender, DrawItemEventArgs e)
{
    if (e.Index < 0) return;
    //if the item state is selected them change the back color 
    if ((e.State & DrawItemState.Selected) == DrawItemState.Selected)
        e = new DrawItemEventArgs(e.Graphics,
                                  e.Font,
                                  e.Bounds,
                                  e.Index,
                                  e.State ^ DrawItemState.Selected,
                                  e.ForeColor,
                                  Color.FromArgb(43, 144, 188));//Choose the color

    // Draw the background of the ListBox control for each item.
    e.DrawBackground();
    // Draw the current item text
    e.Graphics.DrawString(lb_result.Items[e.Index].ToString(), e.Font, Brushes.Black, e.Bounds, StringFormat.GenericDefault);
    // If the ListBox has focus, draw a focus rectangle around the selected item.
    e.DrawFocusRectangle();
}

But I'm now using ListView.

  1. I set OwnerDraw to True
  2. I set DrawItem to ListView1_DrawItem

...and use the code from above.

I expected it to show me a different selection color as stated, but instead I get a few errors:

errors

How would I use this code correctly for a ListView?

See Question&Answers more detail:os

与恶龙缠斗过久,自身亦成为恶龙;凝视深渊过久,深渊将回以凝视…
Welcome To Ask or Share your Answers For Others

1 Reply

0 votes
by (71.8m points)

Owner-drawing a ListView control is more complicated than a ListBox control: many more details to take care of. This is an example that considers four View settings of a ListView:
View.Details, View.List, View.Tile and View.SmallIcon.

Only the Text is drawn here (that's why View.LargeIcon is not included), to contain the code to a decent limit.
An example of drawing the Bitmaps included in a ImageList linked to the ListView is here.

Set up the ListView:
Enable your ListView OwnerDraw mode, then subscribe to its DrawItem, DrawSubItem and DrawColumnHeader events as shown in the sample code (mandatory, if you want the ListView to show anything).

The Headers are painted using the default rendering (setting e.DrawDefault = true).

Description of common operations:
The Item Text is drawn using TextRenderer.DrawText: this is the original method used by the ListView to draw its items. It allows to match exactly the default rendering, so we won't notice some mis-alignment of the text.

The DrawItem event is used to draw a custom background in all View modes and will draw the Items' text in all mode except View.Details, where the DrawSubItems event comes into play: we would draw the first Item's text twice, should the DrawItem event perform the same task.

The DrawSubItems event is not called when the View is set to Tile or List.

Details on the code presented here:
A helper method, GetTextAlignment, takes care of setting the Items' alignment, since each Column can have a specific text alignment.

A field, Color listViewSelectionColor, is used to set/change the Color of the select Items. To modify the selection color, set this filed to any value and Invalidate() the ListView: the new Color will be applied immediately.

Sample of the results:

ListView OwnerDraw

bool lvEditMode = false;
Color listViewSelectionColor = Color.Orange;

protected void listView1_DrawItem(object sender, DrawListViewItemEventArgs e)
{
    var lView = sender as ListView;

    if (lvEditMode || lView.View == View.Details) return;
    TextFormatFlags flags = GetTextAlignment(lView, 0);
    Color itemColor = e.Item.ForeColor;

    if (e.Item.Selected) {
        using (var bkBrush = new SolidBrush(listViewSelectionColor)) {
            e.Graphics.FillRectangle(bkBrush, e.Bounds);
        }
        itemColor = e.Item.BackColor;
    }
    else {
        e.DrawBackground();
    }

    TextRenderer.DrawText(e.Graphics, e.Item.Text, e.Item.Font, e.Bounds, itemColor, flags);

    if (lView.View == View.Tile && e.Item.SubItems.Count > 1) {
        var subItem = e.Item.SubItems[1];
        flags = GetTextAlignment(lView, 1);
        TextRenderer.DrawText(e.Graphics, subItem.Text, subItem.Font, e.Bounds, SystemColors.GrayText, flags);
    }
}

private void listView1_DrawSubItem(object sender, DrawListViewSubItemEventArgs e)
{
    var lView = sender as ListView;
    TextFormatFlags flags = GetTextAlignment(lView, e.ColumnIndex);
    Color itemColor = e.Item.ForeColor;

    if (e.Item.Selected && !lvEditMode) {
        if (e.ColumnIndex == 0 || lView.FullRowSelect) {
            using (var bkgrBrush = new SolidBrush(listViewSelectionColor)) {
                e.Graphics.FillRectangle(bkgrBrush, e.Bounds);
            }
            itemColor = e.Item.BackColor;
        }
    }
    else  {
        e.DrawBackground();
    }
    TextRenderer.DrawText(e.Graphics, e.SubItem.Text, e.SubItem.Font, e.Bounds, itemColor, flags);
}

protected void listView1_DrawColumnHeader(object sender, DrawListViewColumnHeaderEventArgs e)
    => e.DrawDefault = true;

private TextFormatFlags GetTextAlignment(ListView lstView, int colIndex)
{
    TextFormatFlags flags = (lstView.View == View.Tile)
        ? (colIndex == 0) ? TextFormatFlags.Default : TextFormatFlags.Bottom
        : TextFormatFlags.VerticalCenter;

    if (lstView.View == View.Details) flags |= TextFormatFlags.LeftAndRightPadding;

    if (lstView.Columns[colIndex].TextAlign != HorizontalAlignment.Left) {
        flags |= (TextFormatFlags)((int)lstView.Columns[colIndex].TextAlign ^ 3);
    }
    return flags;
}

private void listView1_BeforeLabelEdit(object sender, LabelEditEventArgs e) => lvEditMode = true;

private void listView1_AfterLabelEdit(object sender, LabelEditEventArgs e) => lvEditMode = false;  

与恶龙缠斗过久,自身亦成为恶龙;凝视深渊过久,深渊将回以凝视…
OGeek|极客中国-欢迎来到极客的世界,一个免费开放的程序员编程交流平台!开放,进步,分享!让技术改变生活,让极客改变未来! Welcome to OGeek Q&A Community for programmer and developer-Open, Learning and Share
Click Here to Ask a Question

...