How to change combobox items order dynamically

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I have a Combobox which displaying 'a', 'b', 'c', 'd'.
The same Combobox I need to change the display order like 'c', 'a', 'd', 'b'.

Thanks in advance.

I have detailed explain below my code :-

I need to display Colors in my ComboBox but not all dotnet colors, I have to display only my required colors. Code below

private void FillComboBoxBorderColor(MoeValueMCInfo mcInfo)
{
comboBox_BorderColor.Items.Clear();
float mcVersion = 0;
if (float.TryParse(mcInfo.Version.StringValue, out mcVersion))
{
if (mcInfo.Level.ToString() == "Enterprise" && mcVersion >= 4.0)
{
Dictionary<string, string> deviceSupportedColors = new Dictionary<string, string>();
deviceSupportedColors.Add("0", "OrangeRed");
deviceSupportedColors.Add("1", "Orange");
deviceSupportedColors.Add("2", "Yellow");

//List<string> deviceSupportedColors = new List<string> { "OrangeRed", "Orange", "Yellow", "LawnGreen", "MediumSpringGreen", "Aqua", "CadetBlue", "SlateBlue", "Violet", "Magenta", "MediumVioletRed", "Gray"};
ArrayList ColorList = new ArrayList();
Type colorType = typeof(System.Drawing.Color);
PropertyInfo[] propInfoList = colorType.GetProperties(BindingFlags.Static |
BindingFlags.DeclaredOnly | BindingFlags.Public);
foreach (PropertyInfo c in propInfoList)
{
if (deviceSupportedColors.ContainsValue(c.Name))
{
/*int indextoInsert = Convert.ToInt32((from d in deviceSupportedColors
where d.Value == c.Name
select d.Key).FirstOrDefault()); */

//comboBox_BorderColor.Items.Insert(indextoInsert, c.Name);
this.comboBox_BorderColor.Items.Add(c.Name); 
}
}
}
}
}

So In that I need to display the ComboBox order would be

OrangeRed", "Orange", "Yellow", "LawnGreen", "MediumSpringGreen", "Aqua", "CadetBlue", "SlateBlue", "Violet", "Magenta", "MediumVioletRed", "Gray"

I tried using index but I could not achieve it. (My code mentioned in the command line)

What I have tried:

I used Index but that could not able to achieve.

Posted 8-Jul-17 3:32am

vasanthkumarmk

Updated 8-Jul-17 5:53am

v3

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Maciej Los 8-Jul-17 9:47am

Please, provide your code. Use "Improve question" widget.

vasanthkumarmk 8-Jul-17 10:11am

I need to display in the order of 'OrangeRed', 'Orange', 'Yellow' (mentioned in the List comment line).

2 solutions

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Michael_Davies · Accepted Answer · 2017-07-08T03:57:00

Solution 1

Unless it is a natural sort order the best way is to sort the items in the combobox in a list or array into the order you want then clear the combobox and put the new sorted list back, make sure .sorted=false on the control.

It would be easier to make a suggestion if I knew how you determine the sort order, what makes c come first in your new sorted list?

C#

private void Form1_Load(object sender, EventArgs e)
        {
            Dictionary<string, string> deviceSupportedColors = new Dictionary<string, string>();
            Dictionary<string, string> deviceSortedColors = new Dictionary<string, string>();

            deviceSupportedColors.Add( "OrangeRed", "0");
            deviceSupportedColors.Add( "Orange", "1");
            deviceSupportedColors.Add( "Yellow", "2");

                    //List<string> deviceSupportedColors = new List<string> { "OrangeRed", "Orange", "Yellow", "LawnGreen", "MediumSpringGreen", "Aqua", "CadetBlue", "SlateBlue", "Violet", "Magenta", "MediumVioletRed", "Gray"};
                    ArrayList ColorList = new ArrayList();
                    Type colorType = typeof(System.Drawing.Color);
                    PropertyInfo[] propInfoList = colorType.GetProperties(BindingFlags.Static |
                    BindingFlags.DeclaredOnly | BindingFlags.Public);
                    foreach (PropertyInfo c in propInfoList)
                    {
                        if (deviceSupportedColors.ContainsKey(c.Name))
                        {
                        string keyvalue = " ";

                            deviceSupportedColors.TryGetValue(c.Name, out keyvalue);

                            deviceSortedColors.Add(keyvalue, c.Name);
                        }
                    }
            var list = deviceSortedColors.Keys.ToList();
            list.Sort();

            // Loop through keys.
            foreach (var key in list)
            {
                comboBox1.Items.Add(deviceSortedColors[key]);
        }
        }

Posted 8-Jul-17 3:57am

Michael_Davies

Updated 8-Jul-17 5:15am

v2

Comments

vasanthkumarmk 8-Jul-17 10:03am

In my case I never clear my ComboBox, need to keep the same items in the ComboBox and need to changing the position of the items.

Michael_Davies 8-Jul-17 10:11am

Perfectly clear,

Combobox does not provide a method to allow you to move items around, the list is either sorted if .sorted=true or the items appear in the order yo load them.

So you have to copy the list elsewhere, clear the combobox, sort the list as you wish then put them back into the combobox.

vasanthkumarmk 8-Jul-17 10:24am

I have improved my question, could you please recheck and let me know the answer? Its more helpful

Michael_Davies 8-Jul-17 10:42am

The solution still stands, once you have selected the colours you want you then need to sort them as the order you want is not natural, in your list Orange comes before OrangeRed in the propertyinfo as that is the natural sort order, to get the order you want in a combobox you will have to sort them, now your code is clearer I suggest you create a second dictionary and add the element from the first dictionary if it is found in the propertyinfo then iterate the new dictionary in key order to get the sort you want.

vasanthkumarmk 8-Jul-17 10:49am

Can you pleaseee give small code snap for your recommended.

Michael_Davies 8-Jul-17 11:17am

Added an example to the answer using your code as a base, tested it on a simple form with a combobox called comboBox1, rename it to your box name.

Basically switched your key and values round in the first dictionary as you want the sort order for the color, then add the colors name and the key to the new dictionary, export the keys to a list and sort to get the order you want then populate the combobox in that order.

Michael_Davies 8-Jul-17 11:50am

Quick caveat, if you use a string for the key and have more than 9 colors you'll have a sort problem; "1" & "10" with sort together.

vasanthkumarmk 8-Jul-17 13:11pm

Sorry for interact more with you. You code is working perfect if out keyvalue is not null, but I am getting null for keyvalue

Michael_Davies 8-Jul-17 13:13pm

So test for null and ignore it.

vasanthkumarmk 8-Jul-17 13:35pm

Thanks a lot!!!!! Its really helpfull and resolved my problem. Once again thanks!!! But one final question....
What is the use of Line -> deviceSupportedColors.TryGetValue(c.Name, out keyvalue);

Michael_Davies 8-Jul-17 13:45pm

In .Net Framework a Try<something> attempts to perform the task required, if it fails the answer is usually Null, it does not throw an exception.

Look at Parse and TryParse which are used to convert variables, Parse will throw an exception if the input is unconvertable, TryParse will return True if it succeeded and the target variable will hold the converted value, it will return False if it did not and the target variable will be Null.

For example;

int sdest = Int.Parse("123"); // This will succeed

sdest = Int.Parse("ABC") // This will fail and throw an exception that must be handled

The easiest way is to;

int idest;

if (Int.Tryparse("ABC", out idest) == true)
{ // String converted...all is well idest has the value}
else
{ // conversion failed...go no further idest is Null}

vasanthkumarmk 10-Jul-17 1:00am

Really thanks for your explanation.....

Alan N · Accepted Answer · 2017-07-08T05:53:00

Solution 2

What you are doing seems to be far too complicated. If the Dictionary containing the required order is actually hard coded then all that is required is a list of colours in the correct order. For example:

C#

Color[] deviceColors = new Color[] { Color.OrangeRed, Color.Orange, Color.Yellow };
comboBox_BorderColor.DisplayMember = "Name";
comboBox_BorderColor.DataSource = deviceColors;

Alan.

Posted 8-Jul-17 5:53am

Alan N

Comments

Michael_Davies 8-Jul-17 13:13pm

Quite agree, but if he wants to do it that way...

vasanthkumarmk 8-Jul-17 13:38pm

Thanks Alan N & Michael_Davies both answers helps lot.....