How to check empty DataTable

First make sure that DataTable is not null and than check for the row count

if(dt!=null)
{
  if(dt.Rows.Count>0)
  {
    //do your code 
  }
}

Normally when querying a database with SQL and then fill a data-table with its results, it will never be a null Data table. You have the column headers filled with column information even if you returned 0 records.When one tried to process a data table with 0 records but with column information it will throw exception.To check the datatable before processing one could check like this.

if (DetailTable != null && DetailTable.Rows.Count>0)

If dataTable1 is null, it is not an empty datatable.

Simply wrap your foreach in an if-statement that checks if dataTable1 is null. Make sure that your foreach counts over DataTable1.Rows or you will get a compilation error.

    if (dataTable1 != null)
    {
       foreach (DataRow dr in dataTable1.Rows)
       {
          // ...
       }
    }