how to insert a data table into sql server database table

1 .Create a User-Defined TableType in your database:

CREATE TYPE [dbo].[MyTableType] AS TABLE(
    [Id] int NOT NULL,
    [Name] [nvarchar](128) NULL
)

2. Define a parameter in your Stored Procedure:

CREATE PROCEDURE [dbo].[InsertTable]
    @myTableType MyTableType readonly
AS
BEGIN
    insert into [dbo].Records select * from @myTableType 
END

3. send your DataTable directly to sql server:

using (var command = new SqlCommand("InsertTable") {CommandType = CommandType.StoredProcedure})
{
    var dt = new DataTable(); //create your own data table
    command.Parameters.Add(new SqlParameter("@myTableType", dt));
    SqlHelper.Exec(command);
}

Note: To edit the values inside stored-procedure, you can declare a local variable with the same type and insert input table into it:

DECLARE @modifiableTableType MyTableType 
INSERT INTO @modifiableTableType SELECT * FROM @myTableType
Then, you can edit @modifiableTableType:

UPDATE @modifiableTableType SET [Name] = 'new value'