Colour Individual Items in a winforms ComboBox?
I have a dilemma whereby I have a form which contains a number of comboboxes that contain information/options/items that may be invalid/out-of-date in certain circumstances.
I can't simply remove the out-of-date information from the items, but I do want to give the user a visual-clue when option开发者_运维技巧s are invalid.
I was thinking of colouring in the Items (probably red) to indicate if & when they are invalid. I don't necessarily need to prevent a user from selecting an invalid option, just make them visually aware that they are doing so.
Can this be done? Can you - dyamically - change the colo(u)r of combobox items?
Thanks,
You may try DrawItem event of ComboBox. Keep your dates on a list and compare them with ID's and brush your items.
private void comboBox1_DrawItem(object sender, DrawItemEventArgs e)
{
// Draw the background
e.DrawBackground();
// Get the item text
string text = ((ComboBox)sender).Items[e.Index].ToString();
// Determine the forecolor based on whether or not the item is selected
Brush brush;
if (YourListOfDates[e.Index] < DateTime.Now)// compare date with your list.
{
brush = Brushes.Red;
}
else
{
brush = Brushes.Green;
}
// Draw the text
e.Graphics.DrawString(text, ((Control)sender).Font, brush, e.Bounds.X, e.Bounds.Y);
}
To fire this event (thanks to @Bolu)
You need to change ComboBox.DrawMode to OwnerDrawFixed/OwnerDrawVariable to fire the comboBox_DrawItem
///The ComboBoxCustom Control:
using System;
using System.Windows.Forms;
using System.Drawing;
namespace TyroDeveloper
{
public class ComboBoxCustom:ComboBox
{
public ComboBoxCustom() {
this.DrawMode = System.Windows.Forms.DrawMode.OwnerDrawFixed;
}
protected override void OnDrawItem(DrawItemEventArgs e)
{
base.OnDrawItem(e);
e.DrawBackground();
ComboBoxItem item = (ComboBoxItem)this.Items[e.Index];
Brush brush = new SolidBrush(item.ForeColor);
if ((e.State & DrawItemState.Selected) == DrawItemState.Selected)
{ brush = Brushes.Yellow; }
e.Graphics.DrawString(item.Text, this.Font, brush, e.Bounds.X, e.Bounds.Y);
}
}
public class ComboBoxItem
{
public ComboBoxItem() { }
public ComboBoxItem(string pText, object pValue)
{
text = pText; val = pValue;
}
public ComboBoxItem(string pText, object pValue, Color pColor)
{
text = pText; val = pValue; foreColor = pColor;
}
string text = "";
public string Text {
get { return text; } set { text = value; }
}
object val;
public object Value {
get { return val; } set { val = value; }
}
Color foreColor = Color.Black;
public Color ForeColor {
get { return foreColor; } set { foreColor = value; }
}
public override string ToString()
{
return text;
}
}
}
//To add the items:
comboBoxCustom1.Items.Add(new ComboBoxItem("México","0",Color.Green));
comboBoxCustom1.Items.Add(new ComboBoxItem("USA", "1", Color.Blue));
comboBoxCustom1.Items.Add(new ComboBoxItem("China", "2", Color.Red));
the source url page: http://www.tyrodeveloper.com/2012/04/color-in-combobox-item.html
Changing color of combobox back color
You can use this codes for changing back color of combobox.
using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;
namespace Comboboxrenklendir
{
public partial class Form1 : Form
{
public Form1()
{
InitializeComponent();
}
private void cmbrenkli_DrawItem(object sender, DrawItemEventArgs e)
{
Color HighlightColor = Color.Red;
if (e.Index >=0)
{
//int sayi = cmbrenkli.Items.Count;
string deger = cmbrenkli.Items[e.Index].ToString();
if (deger == "30"|| deger == "50")
{
e.Graphics.FillRectangle(new SolidBrush(HighlightColor), e.Bounds);
}
e.Graphics.DrawString(cmbrenkli.Items[e.Index].ToString(), e.Font, new SolidBrush(cmbrenkli.ForeColor), new Point(e.Bounds.X, e.Bounds.Y));
e.DrawFocusRectangle();
}
}
private void Form1_Load(object sender, EventArgs e)
{
cmbrenkli.Items.Add("10");
cmbrenkli.Items.Add("20");
cmbrenkli.Items.Add("30");
cmbrenkli.Items.Add("40");
cmbrenkli.Items.Add("50");
}
}
}
This should work perfectly
private void comboBox1_DrawItem(object sender, DrawItemEventArgs e)
{
e.DrawBackground();
Color color;
//Text of your ComboBox element
string text = ((ComboBox)sender).Items[e.Index].ToString();
//Check for something
if (text == "I am red")
{
color = Color.Red;
}
else
{
color = Color.White;
}
e.Graphics.FillRectangle(new SolidBrush(color), e.Bounds);
e.Graphics.DrawString(text, e.Font, new SolidBrush(((ComboBox)sender).ForeColor), new Point(e.Bounds.X, e.Bounds.Y));
e.DrawFocusRectangle();
}
Use this as DrawItem Event and set DrawMode to OwnerDrawFixed or OwnerDrawVariable
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