CODEWITHSUNDEEP
c#.netlinqdatatable
Lalit
Lalit

Reputation: 4957

Get all column names of a DataTable into string array using (LINQ/Predicate)

I know we can easily do this by a simple loop, but I want to persue this LINQ/Predicate?

string[] columnNames = dt.Columns.?

or

string[] columnNames = from DataColumn dc in dt.Columns select dc.name;

Upvotes: 140

Views: 276108

Answers (4)

user3233312
user3233312

Reputation: 164

List<String> lsColumns = new List<string>();

if(dt.Rows.Count>0)
{
    var count = dt.Rows[0].Table.Columns.Count;

    for (int i = 0; i < count;i++ )
    {
        lsColumns.Add(Convert.ToString(dt.Rows[0][i]));
    }
}

Upvotes: -1

Sem Vanmeenen
Sem Vanmeenen

Reputation: 2151

Use

var arrayNames = (from DataColumn x 
                  in dt.Columns.Cast<DataColumn>()
                  select x.ColumnName).ToArray();

Upvotes: 19

Daniel Hilgarth
Daniel Hilgarth

Reputation: 174309

Try this (LINQ method syntax): 

string[] columnNames = dt.Columns.Cast<DataColumn>()
                                 .Select(x => x.ColumnName)
                                 .ToArray();

or in LINQ Query syntax: 

string[] columnNames = (from dc in dt.Columns.Cast<DataColumn>()
                        select dc.ColumnName).ToArray();

Cast is required, because Columns is of type DataColumnCollection which is a IEnumerable, not IEnumerable<DataColumn>. The other parts should be obvious.

Upvotes: 286

Deilan
Deilan

Reputation: 4886

I'd suggest using such extension method:

public static class DataColumnCollectionExtensions
{
    public static IEnumerable<DataColumn> AsEnumerable(this DataColumnCollection source)
    {
        return source.Cast<DataColumn>();
    }
}

And therefore:

string[] columnNames = dataTable.Columns.AsEnumerable().Select(column => column.Name).ToArray();

You may also implement one more extension method for DataTable class to reduce code:

public static class DataTableExtensions
{
    public static IEnumerable<DataColumn> GetColumns(this DataTable source)
    {
        return source.Columns.AsEnumerable();
    }
}

And use it as follows:

string[] columnNames = dataTable.GetColumns().Select(column => column.Name).ToArray();

Upvotes: 6

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