save Datatable values as empty string instead of null

I am using an SqlDataAdapter to save some values from a 开发者_开发知识库table to a database:

private BindingSource bindingSource1 = new BindingSource();
private SqlDataAdapter dataAdapter = new SqlDataAdapter();
...
dataAdapter.Update((DataTable) bindingSource1.DataSource);

but it is saving empty values as null in the database. Is there anyway to make it save them as empty strings instead?

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After some research everyone seems to be doing manually so I wrote a method that does that.

  public static DataTable RemoveNulls(DataTable dt)
    {
        for (int a = 0; a < dt.Rows.Count; a++)
        {
            for (int i = 0; i < dt.Columns.Count; i++)
            {
                if (dt.Rows[a][i] == DBNull.Value)
                {
                    dt.Rows[a][i] = "";
                }
            }
        }

        return dt;
    }

and some related links

http://madskristensen.net/post/Remove-nulls-from-a-DataTable.aspx

http://forums.asp.net/t/307989.aspx/1?remove+null+rows+in+data+table

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Have you tried filling the offending fields with String.Empty?