How to add row with default values into System.Data.DataTable

Question

I have DataTable and I need to add row with default values and save it into database.

BONUS: Would be awesome to auto increment key column.

How can I achieve that?

Answer 1

static int i = 1;
private void CreateDefault()
{
    DataColumn column = null;
    DataTable table = new DataTable();

    column = new DataColumn();
    var Col1 = column;
    Col1.DataType = System.Type.GetType("System.Int32");
    Col1.DefaultValue = i;
    Col1.Unique = false;
    table.Columns.Add(column);
    i = i + 1;

    column = new DataColumn();
    var Col2 = column;
    Col2.DataType = System.Type.GetType("System.String");
    Col2.DefaultValue = "Your String";
    table.Columns.Add(column);

    DataRow row = null;
    row = table.NewRow();

    table.Rows.Add(row);
}

Variable i will be auto increment key column. Now Insert the DataTable to DataBase.

Answer 2

You can add a new row with default values and save it into database like this.

using (var conn = new SqlConnection(connectionString))
{
    SqlCommand cmd = new SqlCommand("SELECT * FROM YourTableName", conn);
    SqlDataAdapter da = new SqlDataAdapter() { SelectCommand = cmd };

    // Load records to a DataSet
    DataSet ds = new DataSet();
    da.Fill(ds, "YourTableName");
    var table = ds.Tables["YourTableName"];

    // Add a new row with default value
    table.Rows.Add();

    // Reflect the change to database
    SqlCommandBuilder cb = new SqlCommandBuilder(da);
    da.Update(ds, "YourTableName");
}

Also, if you've set an auto increment key like IDENTITY for MS SQL Server (https://msdn.microsoft.com/en-us/library/ms186775.aspx), this works when the new row is inserted.