Question

i am binding the below data to a drop down but am not able to get disctinct value. Please help. Find the code snippet below

var SalesOrgTypes = (from s in tblSales
                         orderby s.SalesOrg ascending
                         select new DropDownItem
                         {
                             Value = s.SalesOrg,
                             Text = s.SalesOrg + " - " + s.SalesOrgDesc
                         }).Distinct();

Answer 1

Distinct() is using the definied Equals(object obj) method of the DropDownItem. You have to define a proper IEqualityComparer and give it to the Distinct(IEqualityComparer<T>) method to tell Distinct not to use the native Equals(object obj) method, but your own equalization.

class DropDownItemEqualityComparer : IEqualityComparer<DropDownItem>
{
    #region IEqualityComparer<DropDownItem> Member

    public bool Equals(DropDownItem x, DropDownItem y)
    {
        return
            x == null || y == null 
            ? false
            : x.Value == y.Value && x.Text == y.Text; 
        //Or whatever properties you want to be equal
    }

    public int GetHashCode(DropDownItem obj)
    {
        if (obj != null)
            return
                obj.Value.GetHashCode() + obj.Text.GetHashCode();
        else
            throw new ArgumentNullException("obj");
    }

    #endregion
}

Then you can give this to the Distinct method

var SalesOrgTypes = (from s in tblSales
                         orderby s.SalesOrg ascending
                         select new DropDownItem
                         {
                             Value = s.SalesOrg,
                             Text = s.SalesOrg + " - " + s.SalesOrgDesc
                         }).Distinct(new DropDownItemEqualityComparer());