LINQ: Update a column with auto increment value

Question

Hi All,
Greetings.
I am very new to C# (though with lot of experience in VC++). Now a days, I am engaged in a C# project where I need to deal with ADO.NET DataTable and related classes. I am stuck up in a scenario as follows:
I have a data table (of DataTable type) pre-populated with many rows (50000+), parsed from a log file. Now I need to add a column that will be holding index number for each records; eg. 1, 2, 3......
I have tried to add the auto-incremented column dynamically, with seed = 0 and increment = 1, but it is not working.
Is there any LINQ query that I can run to update the DataTable at once? Or foreach loop per DataRow is the only option here?
I appreciate any quick suggestion on this.
Thanks in advance.
Sanjoy Jana.

Answer 1

You should add the auto increment column to the DataTable before you pouplate it with the other data:
//1. Create a datatable
DataTable dt = new DataTable();
//2. add the autoincrement column:
DataColumn column = new DataColumn();
column.DataType = System.Type.GetType("System.Int32");
column.AutoIncrement = true;
column.AutoIncrementStep = 1;
column.AutoIncrementSeed = 1;
//3. Fill the dataTable using an SqlDataAdapter or whatever
dt.Columns.Add(new DataColumn("name"));
dt.Rows.Add("1");
dt.Rows.Add("2");
dt.Rows.Add("3");
dt.Rows.Add("4");
Then you don't have to add the "auto incremented" values yourself in some kind of a loop (using for example LINQ or foreach).
If you want to know how to poplulate the DataTable from a database query using an adapter, please refer to the following page:
http://www.dotnetperls.com/sqldataadapter
Hope that helps.
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