I have a dataset (called dataSet below) with a single table and some records in it. One of the columns is called Message and contains an error message. If any records have a value in this field I want to copy it into an error dataset (errorDataSet below) and then remove it from the original dataset. I managed to get this far with LINQ:
DataSet errorDataSet = dataSet.Copy();
//find all records that have a Message column value
var query = from row in errorDataSet.Tables[0].AsEnumerable()
where !String.IsNullOrEmpty(row.Field<string>("Message"))
select row;
DataSet tempErrorDataSet = errorDataSet.Clone();
foreach (var row in query)
{
tempErrorDataSet.Tables[0].Clear();
tempErrorDataSet.Tables[0].ImportRow(row);
utility.WriteError(connectorName, row["Message"].ToString(), tempErrorDataSet);
//remove the error row from the good data
dataSet.Tables[0].Rows.Remove(row);
}
The bottom line throws an exception or I get errors regarding modifying a collection etc. I'm sure there is a simple way of doing this in LINQ.
Note: The reason I have tempErrorDataSet is that I convert it to XML and pass it into a stored proc - it only takes a record at a time in that format, hence I clear it each time.
Your query is enumerating (indirectly) through the rows in the table. As you should already know, you cannot modify a collection (remove something in this case) as you enumerate over it. Throw the contents into a list beforehand. That way you're not enumerating through the actual table but a copy of some rows.
var query = (from row in errorDataSet.Tables[0].AsEnumerable()
where !String.IsNullOrEmpty(row.Field<string>("Message"))
select row).ToList();
Related
I have Files and Folders models that are related by a many-to-many relationship with a folder_file pivot table.
I want to insert files in bulk using the insert() method, then use the list of inserted ids with the syncWithoutDetaching() method to update the pivot table, | first create the $data_array in a foreach loop that does other things as well:
$data_array = [];
foreach (...) {
// ...
$data_array[] = $row;
}
then I want to insert the data and update the pivot table:
File::insert($data_array);
$folder->files()->syncWithoutDetaching($array_of_inserted_ids);
Is it possible to get the list of inserted ids from the insert() method?
Or maybe there is a more efficient way for better DB performance?
At first I just wanted to create the record and update the pivot table inside the foreach loop that creates the $data_array so that on every iteration it would create and update the tables, but that could be bad for performance with that many queries?
You could use the createMany() here. Instead of inserting the files then get the ids of inserted data. It will accept an array of data so that you could directly insert your array of files then connecting them to the folder.
$folder->files()->createMany($data_array);
I have Documents table and Signs table. Document record can be related with many records in Signs table.
Now, I want to get all records of Documents table when document ID appears in Signs table.
Here I get all documents:
var documents = (from c in context.documents select c);
Here I get all my signs and save into List:
var myDocuments = (from s in context.signs where s.UserId== id select s.ID).ToList();
This list contains collection on document ID.
And here, I'm trying to get all documents that exists in myDocuments list:
documents.Where(item => myDocuments.Contains(item.ID));
But, when I do .ToList() allways return all records (in database only exists one compatible record)
What is wrong in LinQ statement?
The problem is that this statement doesn't modify the contents of documents, it merely returns the results (which you're not doing anything with):
documents.Where(item => myDocuments.Contains(item.ID));
documents is still the full list.
Change this line to something like:
var matchingIDDocs = documents.Where(item => myDocuments.Contains(item.ID));
And then use matchingIDDocs in place of "documents" later in your code.
On my grid, after a user enters text on the bottom row, I am adding another row so they can fill out another row if needed. The grid will grow as needed by the user. This is working fine, however after a page reload and populating from db, the addrowdata() function does not honor existing row ids and creates duplicates, starting from 1 again, e.g. jqg1. It should look at existing row ids and create new unique ids. So if I have 5 rows already, it might start at jqg6. Here is the relevant code inside onCellSelect:
var records = jQuery("#table-1").jqGrid('getGridParam', 'records');
var lastRowId = jQuery("#table-1").jqGrid('getDataIDs')[records - 1];
if (lastRowId == id)
{
jQuery('#table-1').addRowData(undefined, {}, 'last');
}
I have also tried $.jgrid.randId() instead of undefined, same results as expected.
Thanks
Ryan
I think that the error is in the part where you fill grid with the data from the database. The data saved in the database has unique ids. The ids are not in the form jqg1, jqg2, ... So if should be no conflicts. You should just fill the id fields of the JSON with the ids from the database.
One more possibility is that you just specify the rowid parameter (the first parameter) of addRowData yourself. In the case you will have full control on the new ids of the rows added in the grid.
The code of $.jgrid.randId function is very easy. There are $.jgrid.uidPref initialized as 'jqg' and $.jgrid.guid initialized to 1. The $.jgrid.randId function do the following
$.jgrid.randId = function (prefix) {
return (prefix? prefix: $.jgrid.uidPref) + ($.jgrid.guid++);
}
If it is really required you can increase (but not decrease) the $.jgrid.guid value without any negative side effects.
I'm using OpenXML to open a spreadsheet and loop through the rows of a spreadsheet. I have a linq query that returns all cells within a row. The linq query was ripped straight from a demo on the MSDN.
IEnumerable<String> textValues =
from cell in row.Descendants<Cell>()
where cell.CellValue != null
select (cell.DataType != null
&& cell.DataType.HasValue
&& cell.DataType == CellValues.SharedString
? sharedString.ChildElements[int.Parse(cell.CellValue.InnerText)].InnerText
: cell.CellValue.InnerText);
The linq query is great at returning all cells that have a value, but it doesn't return cells that don't have a value. This in turn makes it impossible to tell which cell is which. Let me explain a little more. Say for instance we have three columns in our spreadsheet: Name, SSN, and Address. The way this linq query works is it only returns those cells that have a value for a given row. So if there is a row of data that has "John", "", "173 Sycamore" then the linq query only returns "John" and "173 Sycamore" in the enumeration, which in turn makes it impossible for me to know if "173 Sycamore" is the SSN or the Address field.
Let me reiterate here: what I need is for all cells to be returned, and not just cells that contain a value.
I've tried to monkey the linq query in every way that I could think of, but I had no luck whatsoever (ie - removing the where clause isn't the trick). Any help would be appreciated. Thanks!
The OpenXML standard does not define placeholders for cells that don't have data. In other words, it's underlying storage in XML is sparse. You could work round this on one of two ways:
Create a list of all "available" or "possible" cells (probably by using a CROSS JOIN type of operation) then "left" joining to the row.Descendants<Cell>() collection to see if the cell reference has a value
Utilize a 3rd party tool such as ClosedXML or EPPlus as a wrapper around the Excel data and query their interfaces, which are much more developer-friendly.
With ClosedXML:
var wb = new XLWorkbook("YourWorkbook.xlsx");
var ws = wb.Worksheet("YourWorksheetName");
var range = ws.RangeUsed();
foreach(var row in range.Rows())
{
// Do something with the row...
// ...
foreach(var cell in row.Cells())
{
// Now do something with every cell in the row
// ...
}
}
The one way I recommend is to fill in all the null cells with blank data so they will be returned by your linq statement. See this answer for how to do that.
In the table ReservationWorkerPeriods there are records of all workers that are planned to work on a given period on any possible machine.
The additional table WorkerOnMachineOnConstructionSite contains columns workerId, MachineId and ConstructionSiteId.
From the table ReservationWorkerPeriods I would like to retrieve just workers who work on selected machine.
In order to retrieve just relevant records from WorkerOnMachineOnConstructionSite table I have written the following code:
var relevantWorkerOnMachineOnConstructionSite = (from cswm in currentConstructionSiteSchedule.ContrustionSiteWorkerOnMachine
where cswm.MachineId == machineId
select cswm).ToList();
workerOnMachineOnConstructionSite = relevantWorkerOnMachineOnConstructionSite as List<ContrustionSiteWorkerOnMachine>;
These records are also used in the application so I don't want to bypass the above code even if is possible to directly retrieve just workerPeriods for workers who work on selected machine. Anyway I haven't figured out how it is possible to retrieve the relevant workerPeriods once we know which userIDs are relevant.
I have tried the following code:
var userIDs = from w in workerOnMachineOnConstructionSite select new {w.WorkerId};
List<ReservationWorkerPeriods> workerPeriods = currentConstructionSiteSchedule.ReservationWorkerPeriods.ToList();
allocatedWorkers = workerPeriods.Where(wp => userIDs.Contains(wp.WorkerId));
but it seems to be incorrect and don't know how to fix it. Does anyone know what is the problem and how it is possible to retrieve just records which contain userIDs from the list?
Currently, you are constructing an anonymous object on the fly, with one property. You'll want to grab the id directly with (note the missing curly braces):
var userIDs = from w in workerOnMachineOnConstructionSite select w.WorkerId;
Also, in such cases, don't call ToList on it - the variable userIDs just contains the query, not the result. If you use that variable in a further query, the provider can translate it to a single sql query.