[C#] Background color of a ListBox item (winforms)


Answers

Thanks for the answer by Grad van Horck, it guided me in the correct direction.

To support text (not just background color) here is my fully working code:

//global brushes with ordinary/selected colors
private SolidBrush reportsForegroundBrushSelected = new SolidBrush(Color.White);
private SolidBrush reportsForegroundBrush = new SolidBrush(Color.Black);
private SolidBrush reportsBackgroundBrushSelected = new SolidBrush(Color.FromKnownColor(KnownColor.Highlight));
private SolidBrush reportsBackgroundBrush1 = new SolidBrush(Color.White);
private SolidBrush reportsBackgroundBrush2 = new SolidBrush(Color.Gray);

//custom method to draw the items, don't forget to set DrawMode of the ListBox to OwnerDrawFixed
private void lbReports_DrawItem(object sender, DrawItemEventArgs e)
{
    e.DrawBackground();
    bool selected = ((e.State & DrawItemState.Selected) == DrawItemState.Selected);

    int index = e.Index;
    if (index >= 0 && index < lbReports.Items.Count)
    {
        string text = lbReports.Items[index].ToString();
        Graphics g = e.Graphics;

        //background:
        SolidBrush backgroundBrush;
        if (selected)
            backgroundBrush = reportsBackgroundBrushSelected;
        else if ((index % 2) == 0)
            backgroundBrush = reportsBackgroundBrush1;
        else
            backgroundBrush = reportsBackgroundBrush2;
        g.FillRectangle(backgroundBrush, e.Bounds);

        //text:
        SolidBrush foregroundBrush = (selected) ? reportsForegroundBrushSelected : reportsForegroundBrush;
        g.DrawString(text, e.Font, foregroundBrush, lbReports.GetItemRectangle(index).Location);
    }

    e.DrawFocusRectangle();
}

The above adds to the given code and will show the proper text plus highlight selected item.

Question

How can I set the background color of a specific item in a System.Windows.Forms.ListBox? I would like to be able to set multiple ones if possible.




I find solution that instead of using ListBox I used ListView.It allows to change list items BackColor.

private void listView1_Refresh()
{
    for (int i = 0; i < listView1.Items.Count; i++)
    {
        listView1.Items[i].BackColor = Color.Red;
        for (int j = 0; j < existingStudents.Count; j++)
        {
            if (listView1.Items[i].ToString().Contains(existingStudents[j]))
            {
                listView1.Items[i].BackColor = Color.Green;
            }
        }
    }
}



C# : change listbox items color

Assuming WinForms, this is what I would do:

Start by making a class to contain the item to add to the listbox.

public class MyListBoxItem {
    public MyListBoxItem(Color c, string m) { 
        ItemColor = c; 
        Message = m;
    }
    public Color ItemColor { get; set; }
    public string Message { get; set; }
}

Add items to your listbox using this code:

listBox1.Items.Add(new MyListBoxItem(Colors.Green, "Validated data successfully"));
listBox1.Items.Add(new MyListBoxItem(Colors.Red, "Failed to validate data"));

In the properties of the ListBox, set DrawMode to OwnerDrawFixed, and create an event handler for the DrawItem event. This allows you to draw each item however you wish.

In the DrawItem Event:

private void listBox1_DrawItem(object sender, DrawItemEventArgs e)
{
    MyListBoxItem item = listBox1.Items[e.Index] as MyListBoxItem; // Get the current item and cast it to MyListBoxItem
    if (item != null) 
    {
        e.Graphics.DrawString( // Draw the appropriate text in the ListBox
            item.Message, // The message linked to the item
            listBox1.Font, // Take the font from the listbox
            new SolidBrush(item.ItemColor), // Set the color 
            0, // X pixel coordinate
            e.Index * listBox1.ItemHeight // Y pixel coordinate.  Multiply the index by the ItemHeight defined in the listbox.
        );
    }
    else 
    {
         // The item isn't a MyListBoxItem, do something about it
    }
}

There are a few limitations - the main one being that you'd need to write your own click handler and redraw appropriate items to make them appear selected, since Windows won't do that in OwnerDraw mode. However, if this is just intended to be a log of things happening in your application, you may not care about items appearing selectable.

To scroll to the last item try

listBox1.TopIndex = listBox1.Items.Count - 1;



How about

            MyLB is a listbox

            Label ll = new Label();
            ll.Width = MyLB.Width;
            ll.Content = ss;
            if(///<some condition>///)
                ll.Background = Brushes.LightGreen;
            else
                ll.Background = Brushes.LightPink;
            MyLB.Items.Add(ll);



Change a ListBox Background Color

You can try the following and see if it works for you

Probably the only way to accomplish that is to draw the items yourself.

Set the DrawMode to OwnerDrawFixed

and code something like this on the DrawItem event:

private void listBox_DrawItem(object sender, DrawItemEventArgs e)
{
    e.DrawBackground();
    Graphics myCustomGraphic = e.Graphics;
    myCustomGraphic.FillRectangle(new SolidBrush(Color.Yellow), e.Bounds);
    // Print text
    e.DrawFocusRectangle();
}