CODEWITHSUNDEEP
asp.netdatatableado.net
GROVER_SYAAN
GROVER_SYAAN

Reputation: 365

ADO.net Datatable iterating through a column of each data row

i have got a store procedure returning 4 different tables, so i have created four different datatable objects

DataTable dt1 = ds.Tables[0];
DataTable dt2 = ds.Tables[1];
DataTable dt3 = ds.Tables[2];
DataTable dt4 = ds.Tables[3];

the second table dt2 contains two columns address and completed 

address1................12

address2.................9

address3................14

address4................13

i want to loop through second datatable and add all completed values and store it in local variable comp my solution as as follow 

int comp = 0;
foreach (DataRow dr in dt2.Rows)
{
    object o = dr["Completed"];
    comp =+ Convert.ToInt32(o);
}

but output of comp is 13 but it should be 48 sum of last column second datatable, any ideas

Upvotes: 1

Views: 888

Answers (2)

Habib
Habib

Reputation: 223322

Adil has rightly pointed out to the mistake , you can also use LINQ To DataSet/DataTable to compute SUM like:

int comp = dt2.AsEnumerable()
              .Sum(r => r.Field<int>("Completed"));

Or you can use DataTable.Compute like:

int comp = Convert.ToInt32(dt2.Compute("Sum(Completed)", ""));

Upvotes: 2

Adil
Adil

Reputation: 148150

You are using wrong operator for assignment with addition You need += instead of =+. The operator you have =+ mean you have + unary addition operator with +Convert.ToInt32(o) and result is assigned to object o

comp =+ Convert.ToInt32(o);

Means 

comp = +Convert.ToInt32(o); Addition operator will be considered unary operator with Convert.ToInt32(o)

Your code would be

foreach (DataRow dr in dt2.Rows)
{

    object o = dr["Completed"];
    comp += Convert.ToInt32(o);
}

If the left operand of a += or -= operator is classified as an event access, then the expression is evaluated as follows:

  • The instance expression, if any, of the event access is evaluated.
  • The right operand of the += or -= operator is evaluated, and, if required, converted to the type of the left operand through an implicit conversion (Section 6.1).
  • An event accessor of the event is invoked, with the argument list consisting of the right operand, after evaluation and, if necessary, conversion. If the operator was +=, the add accessor is invoked. If the operator was -=, the remo ve accessor is invoked, MSDN.

Upvotes: 2

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