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c#.netwinformscomboboxenums
Tony Miletto
Tony Miletto

Reputation:

Binding an enum to a WinForms combo box, and then setting it

a lot of people have answered the question of how to bind an enum to a combo box in WinForms. Its like this:

comboBox1.DataSource = Enum.GetValues(typeof(MyEnum));

But that is pretty useless without being able to set the actual value to display.

I have tried:

comboBox1.SelectedItem = MyEnum.Something; // Does not work. SelectedItem remains null

I have also tried:

comboBox1.SelectedIndex = Convert.ToInt32(MyEnum.Something); // ArgumentOutOfRangeException, SelectedIndex remains -1

Does anyone have any ideas how to do this?

Upvotes: 142

Views: 241271

Answers (28)

dr.Crow
dr.Crow

Reputation: 1563

To simplify:

First Initialize this command: (e.g. after InitalizeComponent())

yourComboBox.DataSource =  Enum.GetValues(typeof(YourEnum));

To retrieve selected item on combobox:

YourEnum selectedValue = (YourEnum) yourComboBox.SelectedItem;

If you want to set value for the combobox:

yourComboBox.SelectedItem = YourEnum.Foo;

Upvotes: 57

Shrey
Shrey

Reputation: 63

This worked for me:

comboBox1.DataSource = Enum.GetValues(typeof(MyEnum));
comboBox1.SelectedIndex = comboBox1.FindStringExact(MyEnum.something.ToString());

Upvotes: 4

Jordan
Jordan

Reputation: 9911

This is probably never going to be seen among all the other responses, but this is the code I came up with, this has the benefit of using the DescriptionAttribute if it exists, but otherwise using the name of the enum value itself.

I used a dictionary because it has a ready made key/value item pattern. A List<KeyValuePair<string,object>> would also work and without the unnecessary hashing, but a dictionary makes for cleaner code.

I get members that have a MemberType of Field and that are literal. This creates a sequence of only members that are enum values. This is robust since an enum cannot have other fields. 

public static class ControlExtensions
{
    public static void BindToEnum<TEnum>(this ComboBox comboBox)
    {
        var enumType = typeof(TEnum);

        var fields = enumType.GetMembers()
                              .OfType<FieldInfo>()
                              .Where(p => p.MemberType == MemberTypes.Field)
                              .Where(p => p.IsLiteral)
                              .ToList();

        var valuesByName = new Dictionary<string, object>();

        foreach (var field in fields)
        {
            var descriptionAttribute = field.GetCustomAttribute(typeof(DescriptionAttribute), false) as DescriptionAttribute;

            var value = (int)field.GetValue(null);
            var description = string.Empty;

            if (!string.IsNullOrEmpty(descriptionAttribute?.Description))
            {
                description = descriptionAttribute.Description;
            }
            else
            {
                description = field.Name;
            }

            valuesByName[description] = value;
        }

        comboBox.DataSource = valuesByName.ToList();
        comboBox.DisplayMember = "Key";
        comboBox.ValueMember = "Value";
    }


}

Upvotes: 12

Gratzy
Gratzy

Reputation: 2908

None of these worked for me, but this did (and it had the added benefit of being able to have a better description for the name of each enum). I'm not sure if it's due to .net updates or not, but regardless I think this is the best way. You'll need to add a reference to:

using System.ComponentModel;

enum MyEnum
{
    [Description("Red Color")]
    Red = 10,
    [Description("Blue Color")]
    Blue = 50
}

....

    private void LoadCombobox()
    {
        cmbxNewBox.DataSource = Enum.GetValues(typeof(MyEnum))
            .Cast<Enum>()
            .Select(value => new
            {
                (Attribute.GetCustomAttribute(value.GetType().GetField(value.ToString()), typeof(DescriptionAttribute)) as DescriptionAttribute).Description,
                value
            })
            .OrderBy(item => item.value)
            .ToList();
        cmbxNewBox.DisplayMember = "Description";
        cmbxNewBox.ValueMember = "value";
    }

Then when you want to access the data use these two lines:

        Enum.TryParse<MyEnum>(cmbxNewBox.SelectedValue.ToString(), out MyEnum proc);
        int nValue = (int)proc;

Upvotes: 2

Morteza Najafian
Morteza Najafian

Reputation: 11

You can use a extension method

 public static void EnumForComboBox(this ComboBox comboBox, Type enumType)
 {
     var memInfo = enumType.GetMembers().Where(a => a.MemberType == MemberTypes.Field).ToList();
     comboBox.Items.Clear();
     foreach (var member in memInfo)
     {
         var myAttributes = member.GetCustomAttribute(typeof(DescriptionAttribute), false);
         var description = (DescriptionAttribute)myAttributes;
         if (description != null)
         {
             if (!string.IsNullOrEmpty(description.Description))
             {
                 comboBox.Items.Add(description.Description);
                 comboBox.SelectedIndex = 0;
                 comboBox.DropDownStyle = ComboBoxStyle.DropDownList;
             }
         }   
     }
 }

How to use ... Declare enum 

using System.ComponentModel;

public enum CalculationType
{
    [Desciption("LoaderGroup")]
    LoaderGroup,
    [Description("LadingValue")]
    LadingValue,
    [Description("PerBill")]
    PerBill
}

This method show description in Combo box items

combobox1.EnumForComboBox(typeof(CalculationType));

Upvotes: 1

Victor Gomez
Victor Gomez

Reputation: 1

only use casting this way:

if((YouEnum)ComboBoxControl.SelectedItem == YouEnum.Español)
{
   //TODO: type you code here
}

Upvotes: 0

jmservera
jmservera

Reputation: 6682

The code

comboBox1.SelectedItem = MyEnum.Something;

is ok, the problem must reside in the DataBinding. DataBinding assignments occur after the constructor, mainly the first time the combobox is shown. Try to set the value in the Load event. For example, add this code:

protected override void OnLoad(EventArgs e)
{
    base.OnLoad(e);
    comboBox1.SelectedItem = MyEnum.Something;
}

And check if it works.

Upvotes: 15

ncoder83
ncoder83

Reputation: 183

Let's say you have the following enum

public enum Numbers {Zero = 0, One, Two};

You need to have a struct to map those values to a string:

public struct EntityName
{
    public Numbers _num;
    public string _caption;

    public EntityName(Numbers type, string caption)
    {
        _num = type;
        _caption = caption;
    }

    public Numbers GetNumber() 
    {
        return _num;
    }

    public override string ToString()
    {
        return _caption;
    }
}

Now return an array of objects with all the enums mapped to a string:

public object[] GetNumberNameRange()
{
    return new object[]
    {
        new EntityName(Number.Zero, "Zero is chosen"),
        new EntityName(Number.One, "One is chosen"),
        new EntityName(Number.Two, "Two is chosen")
    };
}

And use the following to populate your combo box:

ComboBox numberCB = new ComboBox();
numberCB.Items.AddRange(GetNumberNameRange());

Create a function to retrieve the enum type just in case you want to pass it to a function

public Numbers GetConversionType() 
{
    EntityName type = (EntityName)numberComboBox.SelectedItem;
    return type.GetNumber();           
}

and then you should be ok :)

Upvotes: 13

Tarc
Tarc

Reputation: 3332

Based on the answer from @Amir Shenouda I end up with this:

Enum's definition:

public enum Status { Active = 0, Canceled = 3 };

Setting the drop down values from it:

cbStatus.DataSource = Enum.GetValues(typeof(Status));

Getting the enum from the selected item:

Status? status = cbStatus.SelectedValue as Status?;

Upvotes: 3

Stix
Stix

Reputation: 495

A little late to this party ,

The SelectedValue.ToString() method should pull in the DisplayedName . However this article DataBinding Enum and also With Descriptions shows a handy way to not only have that but instead you can add a custom description attribute to the enum and use it for your displayed value if you preferred. Very simple and easy and about 15 lines or so of code (unless you count the curly braces) for everything.

It is pretty nifty code and you can make it an extension method to boot ...

Upvotes: 0

Sherif Hassaneen
Sherif Hassaneen

Reputation: 11

In Framework 4 you can use the following code:

To bind MultiColumnMode enum to combobox for example:

cbMultiColumnMode.Properties.Items.AddRange(typeof(MultiColumnMode).GetEnumNames());

and to get selected index:

MultiColumnMode multiColMode = (MultiColumnMode)cbMultiColumnMode.SelectedIndex;

note: I use DevExpress combobox in this example, you can do the same in Win Form Combobox

Upvotes: 0

caronjudith
caronjudith

Reputation: 19

    public enum Colors
    {
        Red = 10,
        Blue = 20,
        Green = 30,
        Yellow = 40,
    }

comboBox1.DataSource = Enum.GetValues(typeof(Colors));

Full Source...Binding an enum to Combobox

Upvotes: 1

Mickey Perlstein
Mickey Perlstein

Reputation: 4124

 public static void FillByEnumOrderByNumber<TEnum>(this System.Windows.Forms.ListControl ctrl, TEnum enum1, bool showValueInDisplay = true) where TEnum : struct
    {
        if (!typeof(TEnum).IsEnum) throw new ArgumentException("An Enumeration type is required.", "enumObj");

        var values = from TEnum enumValue in Enum.GetValues(typeof(TEnum))
                     select
                        new
                         KeyValuePair<TEnum, string>(   (enumValue), enumValue.ToString());

        ctrl.DataSource = values
            .OrderBy(x => x.Key)

            .ToList();

        ctrl.DisplayMember = "Value";
        ctrl.ValueMember = "Key";

        ctrl.SelectedValue = enum1;
    }
    public static void  FillByEnumOrderByName<TEnum>(this System.Windows.Forms.ListControl ctrl, TEnum enum1, bool showValueInDisplay = true  ) where TEnum : struct
    {
        if (!typeof(TEnum).IsEnum) throw new ArgumentException("An Enumeration type is required.", "enumObj");

        var values = from TEnum enumValue in Enum.GetValues(typeof(TEnum))
                     select 
                        new 
                         KeyValuePair<TEnum,string> ( (enumValue),  enumValue.ToString()  );

        ctrl.DataSource = values
            .OrderBy(x=>x.Value)
            .ToList();

        ctrl.DisplayMember = "Value";
        ctrl.ValueMember = "Key";

        ctrl.SelectedValue = enum1;
    }

Upvotes: 5

Pavel Šub&#237;k
Pavel Šub&#237;k

Reputation: 91

Try this:

// fill list
MyEnumDropDownList.DataSource = Enum.GetValues(typeof(MyEnum));

// binding
MyEnumDropDownList.DataBindings.Add(new Binding("SelectedValue", StoreObject, "StoreObjectMyEnumField"));

StoreObject is my object example with StoreObjectMyEnumField property for store MyEnum value.

Upvotes: 9

Farhad
Farhad

Reputation: 33

That was always a problem. if you have a Sorted Enum, like from 0 to ...

public enum Test
      one
      Two
      Three
 End

you can bind names to combobox and instead of using .SelectedValue property use .SelectedIndex

   Combobox.DataSource = System.Enum.GetNames(GetType(test))

and the

Dim x as byte = 0
Combobox.Selectedindex=x

Upvotes: 0

Rahul
Rahul

Reputation: 1

Generic method for setting a enum as datasource for drop downs

Display would be name. Selected value would be Enum itself

public IList<KeyValuePair<string, T>> GetDataSourceFromEnum<T>() where T : struct,IConvertible
    {
        IList<KeyValuePair<string, T>> list = new BindingList<KeyValuePair<string, T>>();
        foreach (string value in Enum.GetNames(typeof(T)))
        {
            list.Add(new KeyValuePair<string, T>(value, (T)Enum.Parse(typeof(T), value)));
        }
        return list;
    }

Upvotes: 0

Stijn Bollen
Stijn Bollen

Reputation: 396

Convert the enum to a list of string and add this to the comboBox

comboBox1.DataSource = Enum.GetValues(typeof(SomeEnum)).Cast<SomeEnum>();

Set the displayed value using selectedItem

comboBox1.SelectedItem = SomeEnum.SomeValue;

Upvotes: 1

Amir Shenouda
Amir Shenouda

Reputation: 2185

The Enum

public enum Status { Active = 0, Canceled = 3 };

Setting the drop down values from it

cbStatus.DataSource = Enum.GetValues(typeof(Status));

Getting the enum from the selected item

Status status; 
Enum.TryParse<Status>(cbStatus.SelectedValue.ToString(), out status);

Upvotes: 188

Haider Ali
Haider Ali

Reputation: 2795

this is the solution to load item of enum in combobox :

comboBox1.Items.AddRange( Enum.GetNames(typeof(Border3DStyle)));

And then use the enum item as text :

toolStripStatusLabel1.BorderStyle = (Border3DStyle)Enum.Parse(typeof(Border3DStyle),comboBox1.Text);

Upvotes: 3

claybo.the.invincible
claybo.the.invincible

Reputation: 235

comboBox1.DataSource = Enum.GetValues(typeof(MyEnum));

comboBox1.SelectedIndex = (int)MyEnum.Something;

comboBox1.SelectedIndex = Convert.ToInt32(MyEnum.Something);

Both of these work for me are you sure there isn't something else wrong?

Upvotes: 0

Johan
Johan

Reputation: 753

Old question perhaps here but I had the issue and the solution was easy and simple, I found this http://www.c-sharpcorner.com/UploadFile/mahesh/1220/

It makes use of the databining and works nicely so check it out.

Upvotes: 0

Proteux
Proteux

Reputation: 213

public Form1()
{
    InitializeComponent();
    comboBox.DataSource = EnumWithName<SearchType>.ParseEnum();
    comboBox.DisplayMember = "Name";
}

public class EnumWithName<T>
{
    public string Name { get; set; }
    public T Value { get; set; }

    public static EnumWithName<T>[] ParseEnum()
    {
        List<EnumWithName<T>> list = new List<EnumWithName<T>>();

        foreach (object o in Enum.GetValues(typeof(T)))
        {
            list.Add(new EnumWithName<T>
            {
                Name = Enum.GetName(typeof(T), o).Replace('_', ' '),
                Value = (T)o
            });
        }

        return list.ToArray();
    }
}

public enum SearchType
{
    Value_1,
    Value_2
}

Upvotes: 2

ScottE
ScottE

Reputation: 21630

I use the following helper method, which you can bind to your list.

    ''' <summary>
    ''' Returns enumeration as a sortable list.
    ''' </summary>
    ''' <param name="t">GetType(some enumeration)</param>
    Public Shared Function GetEnumAsList(ByVal t As Type) As SortedList(Of String, Integer)

        If Not t.IsEnum Then
            Throw New ArgumentException("Type is not an enumeration.")
        End If

        Dim items As New SortedList(Of String, Integer)
        Dim enumValues As Integer() = [Enum].GetValues(t)
        Dim enumNames As String() = [Enum].GetNames(t)

        For i As Integer = 0 To enumValues.GetUpperBound(0)
            items.Add(enumNames(i), enumValues(i))
        Next

        Return items

    End Function

Upvotes: 1

Tony Miletto
Tony Miletto

Reputation:

At the moment I am using the Items property rather than the DataSource, it means I have to call Add for each enum value, but its a small enum, and its temporary code anyway.

Then I can just do the Convert.ToInt32 on the value and set it with SelectedIndex.

Temporary solution, but YAGNI for now.

Cheers for the ideas, I will probably use them when I do the proper version after getting a round of customer feedback.

Upvotes: 0

Mehmet Aras
Mehmet Aras

Reputation: 5374

You can use a list of KeyValuePair values as the datasource for the combobox. You will need a helper method where you can specify the enum type and it returns IEnumerable> where int is the value of enum and string is the name of the enum value. In your combobox, set, DisplayMember property to 'Key' and ValueMember property to 'Value'. Value and Key are public properties of KeyValuePair structure. Then when you set SelectedItem property to an enum value like you are doing, it should work.

Upvotes: 0

Abe Lincoln
Abe Lincoln

Reputation:

You could use the "FindString.." functions:

Public Class Form1
    Public Enum Test
        pete
        jack
        fran
        bill
    End Enum
    Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
        ComboBox1.DataSource = [Enum].GetValues(GetType(Test))
        ComboBox1.SelectedIndex = ComboBox1.FindStringExact("jack")
        ComboBox1.SelectedIndex = ComboBox1.FindStringExact(Test.jack.ToString())
        ComboBox1.SelectedIndex = ComboBox1.FindStringExact([Enum].GetName(GetType(Test), Test.jack))
        ComboBox1.SelectedItem = Test.bill
    End Sub
End Class

Upvotes: 0

bruno conde
bruno conde

Reputation: 48255

comboBox1.SelectedItem = MyEnum.Something;

should work just fine ... How can you tell that SelectedItem is null?

Upvotes: 0

rein
rein

Reputation: 33465

Try:

comboBox1.SelectedItem = MyEnum.Something;

EDITS:

Whoops, you've tried that already. However, it worked for me when my comboBox was set to be a DropDownList.

Here is my full code which works for me (with both DropDown and DropDownList):

public partial class Form1 : Form
{
    public enum BlahEnum
    { 
        Red,
        Green,
        Blue,
        Purple
    }

    public Form1()
    {
        InitializeComponent();

        comboBox1.DataSource = Enum.GetValues(typeof(BlahEnum));

    }

    private void button1_Click(object sender, EventArgs e)
    {
        comboBox1.SelectedItem = BlahEnum.Blue;
    }
}

Upvotes: 14

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