How to Bind An Enum Name and Value to an ASP.NET DropDownList

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I had recently written a blog post on How to Bind an ASP.NET DropDownList to an Enumeration with two lines of code. A devcurry reader mailed back asking if it was possible to bind an Enumeration Name and Value to the DropDownList. Here’s how:

<asp:DropDownList ID="DropDownList1" runat="server">
</asp:DropDownList>

C#

enum Speed
{
    Low = 1,
    Medium = 2,
    High = 3
}

protected void Page_Load(object sender, EventArgs e)
{
    Hashtable htSpeed = BindEnum(typeof(Speed));      
    DropDownList1.DataSource = htSpeed;
    DropDownList1.DataValueField = "key";
    DropDownList1.DataTextField = "value";
    DropDownList1.DataBind();
}

protected Hashtable BindEnum(Type speedEnum)
{
    string[] enumNm = Enum.GetNames(speedEnum);
    int[] enumVal = (int[])Enum.GetValues(speedEnum);

    Hashtable htSpeed = new Hashtable();
    for (int cnt = 0; cnt < enumVal.Length; cnt++)
    {
        htSpeed.Add(enumVal.GetValue(cnt), enumNm[cnt]);
    }
    return htSpeed;
}

VB.NET

    Friend Enum Speed
        Low = 1
        Medium = 2
        High = 3
    End Enum

    Protected Sub Page_Load(ByVal sender As Object, ByVal e As EventArgs)
        Dim htSpeed As Hashtable = BindEnum(GetType(Speed))
        DropDownList1.DataSource = htSpeed
        DropDownList1.DataValueField = "key"
        DropDownList1.DataTextField = "value"
        DropDownList1.DataBind()
    End Sub

    Protected Function BindEnum(ByVal speedEnum As Type) As Hashtable
        Dim enumNm() As String = System.Enum.GetNames(speedEnum)
        Dim enumVal() As Integer = _

                  CType(System.Enum.GetValues(speedEnum), Integer())

        Dim htSpeed As New Hashtable()
        For cnt As Integer = 0 To enumVal.Length - 1
            htSpeed.Add(enumVal.GetValue(cnt), enumNm(cnt))
        Next cnt
        Return htSpeed
    End Function

Note 1: You need not have to explicitly create a HashTable and then bind it to a DropDownList,

as shown in this example. Instead, you can also directly (quick and dirty) use:

DropDownList1.Items.Add(new ListItem(string text, string value));

I although prefer it the HashTable way since I can refer it at multiple places and it also looks neat to keep stuff seperate in your code!

Note 2: If you want the DropDownList to be sorted based on the value, just reverse the loop.

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About The Author

Suprotim Agarwal, Developer Technologies MVP (Microsoft Most Valuable Professional) is the founder and contributor for DevCurry, DotNetCurry and SQLServerCurry. He is the Chief Editor of a Developer Magazine called DNC Magazine. He has also authored two Books - 51 Recipes using jQuery with ASP.NET Controls. and The Absolutely Awesome jQuery CookBook.

Follow him on twitter @suprotimagarwal.