How to update whole datatable with for loop in C#

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I want to update whole datatable in c# connected to access(oledb) using for loop, datatable is ok, connection is ok, the problem is, update just runs on first row and other rows are unchanged. here is my code:

OleDbCommand1.CommandText = "UPDATE data Set [pivot] =@pivot WHERE [ID] = @id";
           for (int i = 0; i < n; i++)
           {

               float OP =float.Parse(dt.Rows[i]["openPrice"].ToString());
               float CP = float.Parse(dt.Rows[i]["closePrice"].ToString());
               float HP = float.Parse(dt.Rows[i]["highPrice"].ToString());

               pivotValue = (OP + CP + HP) / 3;
               pivotValueString = pivotValue.ToString();

               OleDbCommand1.Parameters.AddWithValue("@pivot", pivotValueString);
               OleDbCommand1.Parameters.AddWithValue("@id", int.Parse(dt.Rows[i]["ID"].ToString()));

              // OleDbCommand1.CommandText = "UPDATE data Set [pivot] =@pivot WHERE [ID] = @id";

               OleDbCommand1.ExecuteNonQuery();



           }

What I have tried:

I changed the place of OleDbCommand1.CommandText , inside and outside of for loop, but nothing changed.
I will be glad if anybody helps.

Posted 11-Dec-19 2:05am

sepidehGandom

Updated 11-Dec-19 3:54am

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ZurdoDev 11-Dec-19 8:19am

Debug it and find out what is happening. For example, check int.Parse(dt.Rows[i]["ID"].ToString() every time it runs through the loop.

You also need to clear your parameters inside the loop since you always call AddWithValue. OleDbCommand1.Parameters.Clear();

Just do some basic debugging and you should be able to find out very quickly what's going on.

sepidehGandom 11-Dec-19 23:59pm

Thanks a lot, it worked, I did not know this code, you really saved my energy

Richard MacCutchan 11-Dec-19 11:00am

Why are you converting values to strings just so you can convert them back to numbers? And you should not use floats for financial values; use int or decimal types.

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F-ES Sitecore · Accepted Answer · 2019-12-11T03:55:00

Solution 1

Try;

OleDbCommand1.Parameters.Clear();
OleDbCommand1.Parameters.AddWithValue("@pivot", pivotValueString);
OleDbCommand1.Parameters.AddWithValue("@id", int.Parse(dt.Rows[i]["ID"].ToString()));

Posted 11-Dec-19 3:55am

F-ES Sitecore