Not clear what you are trying to achieve, but if you want to retrieve the value of your only one row for every column then you have to use the dc.ColumnName property
DataTable dt = mHandler.GetRegistrtationProgress(customer);
foreach (DataColumn dc in dt.Columns)
{
string hutt = dt.Rows[0][dc.ColumnName].ToString();
....
Of course you could simply loop over the column of the row using an indexer
DataRow row = dt.Rows[0];
for(int i = 0; i < dt.Columns.Count; i++)
{
string hutt = row[i].ToString();
There is also the option of the property ItemArray in the DataRow object where every element of the array contains the corresponding value
DataRow row = dt.Rows[0];
for(int i = 0; i < row.ItemArray.Length; i++)
{
string hutt = row.ItemArray[i].ToString();
....