How to group an array list, within a list of records, Linq GroupBy - C# Discussion Boards

We are going to be here all day, I suspect ...

You have a DGV in one form.
It contains data which it is displaying.
That data is organised into rows and columns.
Somewhere in your code, you added data to that DGV, be it by creating individual columns and then adding rows, or by creating a DataTable / Collection which held the data and setting that as the DataSource for the DGV.

You want to use the data in the DGV in a separate method (in a separate Assembly which is a DLL) so that it can output data to an XLSX file.

That means you have to pass the DGV or it's source data to the method in some way via a parameter, or the method has no way to access it and no idea what to write to the file.

Are you with me so far?

"I have no idea what I did, but I'm taking full credit for it." - ThisOldTony
"Common sense is so rare these days, it should be classified as a super power" - Random T-shirt
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Message Closed

modified 17-Nov-20 1:59am.

Excellent.
First off, change the way you fill your DGV. Instead of adding columns and rows directly, create a DataTable instance instead, populate that, adn set that as the DataSource property of the DGV.

The DGV will now display the data and update it as you add items to the underlying DataTable.

When you want to output the data to XLSX, pass the DataTable instance to your method:

C#

private DataTable theSource = new DataTable();
private void FrmMain_Shown(object sender, EventArgs e)
    {
    theSource.Columns.Add("Column 1");
    theSource.Columns.Add("Column 2");
    theSource.Rows.Add("cccc1111", 666);
    myDataGridView.DataSource = theSource;
    }
private void AddButton_Click(object sender, EventArgs e)
    {
    theSource.Rows.Add(DateTime.Now, "hello");
    }

private void OutputButton_Click(object sender, EventArgs e)
    {
    MyDLLAssemblyClass.OutputToXLSX(theSource, @"d:\Test Data\myFile.xslx");
    }

C#

private static void OutputToXLSX(DataTable dt, string outputPath)
    {
    ...
    }

You can then just add a using line for System.Data to your DLL assembly class and use the Row and Column from the DataTable.

Now your DLL file doesn't need to know what the heck the rest of your code is doing, it just wants a DataTable with the data to output.

"I have no idea what I did, but I'm taking full credit for it." - ThisOldTony
"Common sense is so rare these days, it should be classified as a super power" - Random T-shirt
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Oh, and do yourself a favour: stop using /* ... */ to comment methods.
Use /// instead, and VS will fill in the blanks ready for you to add actual information:

C#

/// <summary>
/// 
/// </summary>
/// <param name="storageClass"></param>
/// <returns></returns>
public static string ReadInstanceData(string storageClass)
    {

Fill it in:

C#

/// <summary>
/// Read a storage class from the instance store
/// </summary>
/// <param name="storageClass">Key name of class in store</param>
/// <returns>null if no such class found</returns>
public static string ReadInstanceData(string storageClass)
    {

And now VS can use that for Intellisence if you let it ...

"I have no idea what I did, but I'm taking full credit for it." - ThisOldTony
"Common sense is so rare these days, it should be classified as a super power" - Random T-shirt
AntiTwitter: @DalekDave is now a follower!

I have been working on this for some time now. Google can only take me so far...
So I thought I'd ask you guys and girls for some help...
----
I have a simple C#, WPF application that I've been playing around with to learn C# and WPF.
The code below is working, but its not displaying my menu items correctly. Here is an example of what it looks like (example A) and what it should look like (example b)
---------------------------------------------------------------------------------------
Example A:
---------------------------------------------------------------------------------------
File | Users | Settings | Tools | Help | Login | Exit | Managers | Window1 | Window2
---------------------------------------------------------------------------------------
Example B:
---------------------------------------------------------------------------------------
File | Users | Settings | Tools | Help Login
Exit | | Managers
| Window1
| Window2
---------------------------------------------------------------------------------------
Exit is a ChildItems \ sub menu items of File
Where as Managers, Window1, Window2 are ChildItems of Tools
---------------------------------------------------------------------------------------

My code below is working to a point
1) For my "mainItem", top level MenuItems, it's pulling them from the database correctly and displaying them correctly

2) For my "childItem", the menu items are pulling correctly from the database, but they are not being assigned or linked to their parent menu item correctly.

This is where I think I need some help from you!

---------------------------------------------------------------------------------------
public void PopulateMenu()
{
// MAIN MENU
Grid.SetRow(mainMenu, 0);
mainMenu.IsMainMenu = true;
mainMenu.Padding = new Thickness(5);
mainMenu.FontSize = 14;
mainMenu.HorizontalAlignment = HorizontalAlignment.Stretch;
mainMenu.VerticalAlignment = VerticalAlignment.Top;

// MENU ITEMSPANEL
mainMenu.ItemsPanel = new ItemsPanelTemplate(
new FrameworkElementFactory(
typeof(DockPanel)));

using (var db = new WorkShopContext())
{

foreach (var m in db.Menus
.Where(p => p.mParentId == 0)
.ToList())
{
// ADD MAIN MENUITEMS
if (!string.IsNullOrEmpty(m.mParentId.ToString()))
{
MenuItem mainItem = new MenuItem();
mainItem.Header = m.mHeader;
mainItem.Tag = m.mTag;
mainItem.Click += MenuItem_Click;

if (m.mHeader == "Login")
{
mainItem.HorizontalAlignment = HorizontalAlignment.Right;
}
mainMenu.Items.Add(mainItem);
}
}

AddChildItems();

}
}

private void AddChildItems()
{
foreach (var c in db.Menus
.Where(p => p.mParentId > 0)
.ToList())
{
if (!string.IsNullOrEmpty(c.mParentId.ToString()))
{
MenuItem childItem = new MenuItem();
childItem.Header = c.mHeader;
childItem.Tag = c.mTag;
childItem.Click += MenuItem_Click;

mainMenu.Items.Add(childItem);
}
}

}

---------------------------------------------------------------------------------------

Try passing the mainmenuitem to the addchilditems and then add the childitem to the mainmenuitems collection of menuitems.

You are currently adding the childitem to the mainmenu

Never underestimate the power of human stupidity -
RAH
I'm old. I know stuff - JSOP

Would it be possible for you to point to some examples on CodeProject or provide a C# example, showing me what I would need to do, to correct the code I currently have so far. Any help would be greatly appropriated.

Scratching my head on this.

I have a list of inventory items, and I want to add how many has sold from orders. I can get the inventory, and then loop that inventory to get the "itemNumber", and query the orders to extract only orders that contain that item. But each order can have multiple items sold, so I need to get the "items sold array" within the order.

This is written for MongoDB, and is not really a MongoDB question. I have no clue how to write this in pure Mongo C# driver.

OrderId<br />
OrderNumber<br />
OrderItems = > ItemId<br />
OrderItems = > ItemNumber<br />
OrderItems = > Qty<br />
OrderItems = > Price

I wrote code to get all my inventory items, and used a for each of each item to query the orders. But I can't figure out the GroupBy part, or perhaps GroupBy is not the right solution.

The var in purple below is suggesting the order model, and not the OrderItems within the Order model. I know I constructed the GroupBy wrong, or using GroupBy is just plain wrong.

C#

// Process inventory items
var start = (page * show) - show;
var query = _context.MarketPlaceInventory.Find(mp => mp.MarketChannel.Equals(marketChannel)).SortBy(s => s.ItemNumber);
var totalTask = query.CountDocumentsAsync();
var inventoryTask = query.Skip(start).Limit(show).ToListAsync();

// Wait for inventory to process
await Task.WhenAll(totalTask, inventoryTask);

// Process units sold from orders, bylooping the inventory
foreach (var product in inventoryTask.Result)
{
   var queryFilter = Builders<MarketPlaceOrders>.Filter.ElemMatch(oi => oi.OrderItems, item => item.ItemNumber == product.ItemNumber);
   var ordersTask = _context.MarketPlaceOrders.Find(queryFilter).ToListAsync();
   await Task.WhenAll(ordersTask);

   var orderItems = ordersTask.Result.GroupBy(x => x.OrderItems).Select(item => new MarketPlaceOrderItems() { 
       ItemQty = item.Sum(qty => <code>qty.ItemQty</code>) // This is suggesting the order, and not orderItems 
   });
   Console.Write(orderItems);

}

return new Get_MarketPlaceInventory
{
  Count = totalTask.Result,
  Inventory = inventoryTask.Result,                   
  Page = page,
  Show = show
};

If it ain't broke don't fix it
Discover my world at jkirkerx.com

Inventory: Item #, Quantity on hand (QTY).

Order Item: Item #, Quantity sold (-QTY).

Merge and sum to get the inventory balance (or stock "not committed").

It was only in wine that he laid down no limit for himself, but he did not allow himself to be confused by it.
― Confucian Analects: Rules of Confucius about his food

Hi!

I try to show dynamically a Xamarin CollectionView (as a visual list of multiple notes), by following this tuto: https://medium.com/a-developer-in-making/how-to-work-with-collectionview-in-xamarin-forms-5dc65c50b419[^]
Everything's work fine, until I try to return a list made of data from a Realm database.

So, that code from the tuto is working fine:

C#

return new List<Note>
                {
                new Note() { Category = listFolders[0].IDCategories, Title = listFolders[0].Title, ContentNote = listFolders[0].ContentNote, Image = listFolders[0].Icon },
                new Note() { Category = listFolders[1].IDCategories, Title = listFolders[1].Title, ContentNote = listFolders[1].ContentNote, Image = listFolders[1].Icon },
                new Note() { Category = listFolders[2].IDCategories, Title = listFolders[2].Title, ContentNote = listFolders[2].ContentNote, Image = listFolders[2].Icon },
                };

And it doesn't work when I try to do the same thing, from a Realm database. Something like that:
(there is no errors, it's just show nothing during the debug).

C#

List<Note> list = new List<Note>();
                for (int i = 0; i < countFolders; i++)
                {
                    new Note() { Category = listFolders[i].IDCategories, Title = listFolders[i].Title, ContentNote = listFolders[i].ContentNote, Image = listFolders[i].Icon };
                }

                return list;

And I tried that too:

C#

return new List<Note>
                {
                    for (int i = 0; i < countFolders; i++)
                {
                    new Note() { Category = listFolders[i].IDCategories, Title = listFolders[i].Title, ContentNote = listFolders[i].ContentNote, Image = listFolders[i].Icon };
                }
              
                }

But just after the first bracket, VS Studio say: " } awaited " and " ; awaited ". But I don't know where precisly... And there is no correction suggested.

I'm sure that's probably simple, but as a beginner, I still miss some things.

Thanks!

Member 14992862 wrote:
but with code errors...

We cannot guess what code errors you get or where they occur. Please edit your question and add the full details.

Because it was just to expose something that I've tried, without thinking especially that the solution is there, but maybe:

C#

return new List<Note>
                {
                    for (int i = 0; i < countFolders; i++)
                {
                    new Note() { Category = listFolders[i].IDCategories, Title = listFolders[i].Title, ContentNote = listFolders[i].ContentNote, Image = listFolders[i].Icon };
                }
              
                }

Just after the first bracket, VS Studio say: " } awaited " and " ; awaited ". But I don't know where precisly... And there is no correction suggested.

Thanks!

You can't write a collection initializer like that: it's a list of properties, but you can't use loops in there at all as it uses the Add method on each instance in the list: Object and Collection Initializers - C# Programming Guide | Microsoft Docs[^]

"I have no idea what I did, but I'm taking full credit for it." - ThisOldTony
"Common sense is so rare these days, it should be classified as a super power" - Random T-shirt
AntiTwitter: @DalekDave is now a follower!

You never actually add the new Note to the List (call it something else eg NoteList)

for...
Note X = new Note()...
NoteList.Add(x)

Never underestimate the power of human stupidity -
RAH
I'm old. I know stuff - JSOP

Aaah, yes, I got it! Thanks to you both!

So, the solution is:

C#

List<Note> list = new List<Note>();
                for (int i = 0; i < countFolders; i++)
                {
                    Note AddAllContent = new Note(list) { Category = listFolders[i].IDCategories, Title = listFolders[i].Title, ContentNote = listFolders[i].ContentNote, Image = listFolders[i].Icon };                    
                    list.Add(AddAllContent);
                }
return list;

I'm a C# user. I did some search in Internet but I couldn't find any proper solution for my problem.
I have a DataGridView which adds rows and fill their value only by pressing a button. The input values is achieved from some Textboxes. My last Column is a Dropbox which has 3 defined items. I want to select first Item as a default value when the button is pressed. User can change it manually later.
How can I do this programmatically?

I tried this code for the button (some part of the code):

C#

Int32 LastRow = dataGridView1.Rows.Count - 1;
dataGridView1.Rows[LastRow].Cells[9].Value = new DataGridViewComboBoxCell {  };

The code after "=" is wrong. I don'y know what to write inside curley brackets.
Confused | :confused:

You need parentheses not braces to instantiate an object:

C#

dataGridView1.Rows[LastRow].Cells[9].Value = new DataGridViewComboBoxCell();

You can then add items to the cell. Although it is probably a better idea to create the cell and populate it before you add it to the DataGridView.

Sorry, I am well out of date. Time to go back and put some study time in.

modified 13-Nov-20 8:15am.

The braces are perfectly valid - it's an empty object initializer. Smile | :)

Object and Collection Initializers - C# Programming Guide | Microsoft Docs[^]

You only need the parentheses if you're passing arguments to the constructor, or not using an object initializer.

"These people looked deep within my soul and assigned me a number based on the order in which I joined."
- Homer

Thanks for reminding me; some re-reading to do.

Can you please give me the correct code for this purpose?

You know what's in the combobox, since you created it. If you want to "default" a new row to a particular value, load the "value"; don't go around trying to manipulate the CB, because it doesn't seem to be supported in this case.

And you would make it easier if you specified at the outset if this is Windows Forms or WPF.

It was only in wine that he laid down no limit for himself, but he did not allow himself to be confused by it.
― Confucian Analects: Rules of Confucius about his food

Commented code in c# forms does it affect the performance in any way as i have been told to apply sonarqube in project,while compiling with sonarqube we get errors asking to get the comments in the forms removed.

No. Comments do not affect performance, they are are all removed prior to the EXE file being produced.
Since they do not make it into the EXE they can have no affect on performance whatsoever.

This does not apply just to C#, but every compiled language.

Comments are vital to developers, but they never reach the end user (which some of us are extremely grateful for) except in interpreted languages such as Python where the entire source code is released and parsed as it executes.

"I have no idea what I did, but I'm taking full credit for it." - ThisOldTony
"Common sense is so rare these days, it should be classified as a super power" - Random T-shirt
AntiTwitter: @DalekDave is now a follower!

Today, even "interpreted" languages are frequently JIT-precompiled into some "bytecode" which is then interpreted. In this step, comments are peeled off, and do not affect interpretation of bytecodes. Startup (i.e. the JIT compilation) may be a couple milliseconds slower if the source has many huge comment blocks, but that is a one-time operation; it is not repeated a thousand times if the comment was placed in a loop executed a thousand times.

Some systems cache the bytecode (e.g. for Python: in a .pyc file), so for the next execution of the program, you have no startup delay. (This resembles .net processing where the first use of a CIL assembly invokes a JIT compiler to build native code, which is cached. In the .net case, comments are peeled off in the initial compilation to CIL, and the JIT compilation is from an intermediate language (sort of like bytecode, but different) to native code.)

I guess there are still a number of systems that interpret source code directly, line by line. If a loop is iterated a thousand times, each source line is broken up into tokens, and their semantics determined, a thousand times. But such systems are getting fewer and fewer. Today, even Javascript / HTML is usually converted to some intermediate bytecode before execution.

I was working with Tcl (/Tk) at the time when JIT compilation was introduced, and made some timing tests, comparing the old directly-from-source interpretation against the JIT bytecode alternative. For loops executed a few thousand times, execution were in many cases 5-7 times faster with the bytecodes.

"Compiling" with Sonarqube ...

It's NOT a compiler.

It was only in wine that he laid down no limit for himself, but he did not allow himself to be confused by it.
― Confucian Analects: Rules of Confucius about his food