Linq Help

David Smith

I wanted to know how to write this in linq below. Basically for every row by id in the testTable find the related fk Id in the Log table and insert the row in the LogTable , then set then assigned the Log table to grid.DataSource

foreach (databaseDataSet.testRow testRow in testTable.Rows)
                {

                        foreach (databaseDataSet.logRow logRow in LogTable.Rows)
                        {
                            Import record into LogTable
                        }

                }

               grid.DataSource = LogTable;

5 Replies

Know the answer? Post it — somebody with the same question will find it here.

David Smith14y ago
What i what i really want to do is take the same logic and transefer it to use the row.GetpdataRows() property function, using linq will iterate throught every row, but if you call the row.GetpdataRows() function it will pull only the
right values with out iterating throught all of the records if i can remember. I have quite got it yet, im working on it below.

            //if (dataRow != null)
            //{
            //    databaseDataSet.testRow row = dataRow as databaseDataSet.testRow;

            //    if (row != null)
            //    {

            //        databaseDataSetTableAdapters.pdataTableAdapter ad = new               databaseDataSetTableAdapters.pdataTableAdapter();

            //        ad.Fill(this.databaseDataSet.logTable);

            //        databaseDataSet.pdataRow[] logDataRowsArray = row.GetpdataRows();

                            // logDataRowsArray for some reason is returning null, but when I look in row, it actually has a row, so im not for sure whats going on at the moment


            //    }
            //}
David Smith14y ago
I figure it out earlier, this is what i came up with earlier i meant to post, but i got caught with work.

var testTable = from t in this.testTableAdapter1.GetData()
where t.colorSerialNumber.StartsWith("s")
select t.ToList();

this.ultraGrid1.DataSource = testTable;

var LogTableData = (from c in this.logTableAdapter.GetData()
join td in testTable on c.fk_TestTableId equals td.TestTableId
select c).ToList();

this.ultraGrid2.DataSource = LogTableData ;

Your way and my way works, But I can replace the var with IEnumerable so when i have code review that actually know what the type is.
Vulpes14y ago
I'm not sure whether it's what you had in mind but the best I've been able to come up with is this :

// filter out rows in the LogTable which have a common Id in the two tables

IEnumerable rows = from logRow in LogTable.Rows
from testRow in testTable.Rows
where testRow["TestTableId"].ToString() == logRow["fk_TestTableId"].ToString()
select logRow;

// create a new datatable to house the rows we've filtered out

DataTable LogTable2 = LogTable.Clone();
foreach(DataRow row in rows) LogTable2.Rows.Add(row.ItemArray);
grid.DataSource = LogTable2;:
David Smith14y ago
Below are the made up tables and fields, basically want to find child records or related records using linq. Let me know if this clear

Test Table
LogTable

TestTableId
LogTabId

Race
Description

Job
Error

TestType
fk_TestTableId

foreach (databaseDataSet.testRow testRow in testTable.Rows)
{

      foreach (databaseDataSet.logRow logRow in LogTable.Rows)
      {
          Import record into LogTable or find related records by id
      }

}

grid.DataSource = LogTable;
Vulpes14y ago
It's not possible to answer this without knowing what columns testTable contains, what columns LogTable contains and what the relationship is between the 'id' column in the former and the 'fk Id' column in the latter.

Test Table		LogTable

TestTableId		LogTabId
Race		Description
Job		Error
TestType		fk_TestTableId