C#

String temp;
foreach (DataRow row in Table.Rows)
                    {
                        foreach (DataColumn column in Table.Columns)
                        {
                            if(row[column].ToString().Contains("%"))
                            {
                                temp = row[column].ToString().Replace("%"," ");
                               row[column] = temp;
                            }
                        }
                    }
                    Table.AcceptChanges();
Table is nothing but a datatable...
and when im trying to run the below code... im getting error like input string was not in a correct format  
in the below highlighted line of code..
 String tem;
foreach (DataRow row in Table.Rows)
                {
                    foreach (DataColumn column in Table.Columns)
                    {
                        if (row[column].ToString().Contains(" "))
                        {
                            tem = row[column].ToString().Replace(" ", "%");
                            row[column] = temp; //getting error in this line...
                        }
                    }
                }
                Table.AcceptChanges();