CODEWITHSUNDEEP
c#asp.net
user3452210
user3452210

Reputation: 147

Binding Data text field, Data value field to asp:Dropdownlist

I have created a helper function to Bind Drop down list in asp.net. See my function:

  public void BindDDL(string query, DropDownList DDL)
    {
        List<Issuetype> obj = new List<Issuetype>();
        Issuetype iss = new Issuetype();
        iss.DeptId = 1;
        iss.Issue = "SSS";
        iss.IssuetypeId = 4;
        obj.Add(iss);
        //BALissue Bl = new BALissue();
        //List<Issuetype> objSource = null;
        //objSource = Bl.Bind_issuetypes(query);
        DDL.DataSource = obj;
        DDL.DataValueField = Convert.ToString(obj[0]);
        DDL.DataTextField = Convert.ToString(obj[1]);
        DDL.DataBind();

    }

In this way if i send the query name and Dropdownlist id to the function, drop down should be binded by the List of Issuetype entity, You can see the properties of Issuetype in code.

But however i am not able to Set the DataValueField and DataTextField correctly. Every time it is saying index out of range.

Upvotes: 1

Views: 6058

Answers (3)

vallabha
vallabha

Reputation: 385

Actually there is no obj[1] in your code because you have only one item in the obj list, so at

DDL.DataTextField = Convert.ToString(obj[1]);

this line you will get the exception

Instead you can use

   DDL.DataValueField = "Issue"; 
   DDL.DataTextField = "IssuetypeId";

And to get property names use Reflection

using System.Reflection;  // reflection namespace  
// get all public static properties of MyClass type
PropertyInfo[] propertyInfos;
propertyInfos = typeof(MyClass).GetProperties(BindingFlags.Public | BindingFlags.Static);
// sort properties by name
Array.Sort(propertyInfos,
        delegate(PropertyInfo propertyInfo1, PropertyInfo propertyInfo2)
        { return propertyInfo1.Name.CompareTo(propertyInfo2.Name); });
// write property names
foreach (PropertyInfo propertyInfo in propertyInfos)
{
  Console.WriteLine(propertyInfo.Name);
}

Upvotes: 1

Mrchief
Mrchief

Reputation: 76258

You need to specify the key and value fields. In your case, you're adding one item to list but trying to access the second (non-existent) item while trying to specify the value: Convert.ToString(obj[1]).

What you probably want instead is this:

DDL.DataValueField = "IssuetypeId";
DDL.DataTextField = "Issue";

Upvotes: 1

mybirthname
mybirthname

Reputation: 18137

DataValueField and DataTextField should be names of the field in your collection, not values from the collection.

    DDL.DataSource = obj;
    DDL.DataValueField = "Issue"; //example choose what is needed
    DDL.DataTextField = "IssuetypeId"; //example choose what is needed
    DDL.DataBind();

The exception is thrown because in your collection you have 1 item, but you try to put second item(not exist) in DataTextField. But this is not relevant if you fix your code.

Upvotes: 1

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