C# – vb.net LINQ select Distinct to a List

cdatatablelinqnetvb.net

I have a datatable with a column that has some duplicate values, I want to add those values to a listbox but without duplicates

I tried the following

Dim a = From row In table.AsEnumerable.Distinct.ToList Select row.Field(Of String)("name")

but it gives me duplicate values, How can it be done without duplicates?

Best Answer

I believe there are some more column(s) which are unique in each row that's why the distinct doesn't return the result as expected. Instead you should need to select the columns first than apply the distinct to it.

So try this instead :

Dim a = (From row In table.AsEnumerable()
        Select row.Field(Of String)("name")).Distinct().ToList()

Hope this will help !!

Related Solutions

C# – LINQ query on a DataTable

You can't query against the DataTable's Rows collection, since DataRowCollection doesn't implement IEnumerable<T>. You need to use the AsEnumerable() extension for DataTable. Like so:

var results = from myRow in myDataTable.AsEnumerable()
where myRow.Field<int>("RowNo") == 1
select myRow;

And as @Keith says, you'll need to add a reference to System.Data.DataSetExtensions

AsEnumerable() returns IEnumerable<DataRow>. If you need to convert IEnumerable<DataRow> to a DataTable, use the CopyToDataTable() extension.

Below is query with Lambda Expression,

var result = myDataTable
    .AsEnumerable()
    .Where(myRow => myRow.Field<int>("RowNo") == 1);

Linq – Multiple “order by” in LINQ

This should work for you:

var movies = _db.Movies.OrderBy(c => c.Category).ThenBy(n => n.Name)

Best Answer

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C# – LINQ query on a DataTable

Linq – Multiple “order by” in LINQ

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