如何将DataTable中的空数据设​​置为空字符串

Question

I populated datatable object with data from database, and I need to check if some of them are NULL and set it to empty string .
The problem is that some data are NULL in database but they are "0" in DataTable.
I have tried to set to "" , String.EmptyString etc. nothing works.

foreach (DataRow row in ds.Tables[0].Rows)
{
    foreach (DataColumn c in ds.Tables[0].Columns)
    {
        object value = row[c];

        if (value == DBNull.Value)
        {
            try
            {
                row[c] = "";

Answer 1

try changing to;

foreach (DataRow row in ds.Tables[0].Rows)
{
    foreach (DataColumn c in ds.Tables[0].Columns)
    {
        if (row.IsNull(c))
        {
            try
            {
                row[c] = string.Empty;

The row.IsNull(c) check is more reliable than directly comparing to DBNull.Value as it can evaluate more than one thing as equivilent to NULL in the DB.