C# Discussion Boards - CodeProject

Re: What is the synntax error in this SQLite query?

8-Jul-21 7:57

I had used a similar query in C# and it was working well (SQL server CE):

SQL

mycommand.CommandText = $"INSERT INTO MyData([Wo], [EqN], [Code], [Work], [Cost]) SELECT '{DataGridView3.Rows[i].Cells[0].Value}', '{DataGridView3.Rows[i].Cells[1].Value}', '{DataGridView3.Rows[i].Cells[2].Value}', '{DataGridView3.Rows[i].Cells[3].Value}', '{DataGridView3.Rows[i].Cells[4].Value}' WHERE NOT EXISTS (SELECT 1 FROM MyData WHERE [Wo]='{DataGridView3.Rows[i].Cells[0].Value}' AND [Code]='{DataGridView3.Rows[i].Cells[2].Value}')";

Richard MacCutchan8-Jul-21 21:12

Richard MacCutchan

8-Jul-21 21:12

Yes, but the WHERE clause is connected to the SELECT, not the INSERT.

Re: What is the synntax error in this SQLite query?

Alex Dunlop8-Jul-21 8:50

8-Jul-21 8:50

I found an easy way. I changed EqpCode column type to UNIQUE and Unique Conflict Clause to REPLACE. Smile | :)

Then:

SQL

INSERT INTO FileInfo(EqpCode, EqpName, FileName) VALUES ('123', 'test01', 'test02')
ON CONFLICT(EqpCode) DO UPDATE 
SET EqpName = EXCLUDED.EqpName,
    FileName = EXCLUDED.FileName;

modified 8-Jul-21 15:04pm.

SeeSharp29-Jul-21 5:47

SeeSharp2

9-Jul-21 5:47

Some have given you the answer but not really shown you what they mean. You can't use WHERE without a SELECT. So, you do something like this:

SQL

INSERT INTO Table1(Field1, Field2, ...)
SELECT '2021', 'Alex', ...
WHERE NOT EXISTS (...)

OriginalGriff9-Jul-21 19:04

9-Jul-21 19:04

DevParty wrote:
You can't use WHERE without a SELECT.

Um ... you sure?

SQL

UPDATE MyTable SET MyColumn = @MyValue WHERE MyOtherColumn = @MyOtherValue

"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!

Victor Nijegorodov9-Jul-21 21:39

Victor Nijegorodov

9-Jul-21 21:39

OriginalGriff wrote:
DevParty wrote:
You can't use WHERE without a SELECT.

Um ... you sure?
SQL
Copy Code

SQL
UPDATE MyTable SET MyColumn = @MyValue WHERE MyOtherColumn = @MyOtherValue

I'm pretty sure he meant an INSERT, clause, not an UPDATE one! OMG | :OMG:

OriginalGriff9-Jul-21 22:31

9-Jul-21 22:31

What he may have meant and what he said are not necessarily the same thing! Laugh | :laugh:

Particularly with beginners, you have to be accurate - a bald statement like "WHERE only works with SELECT" is not accurate and can confuse.

Richard Andrew x6410-Jul-21 0:03

Richard Andrew x64

10-Jul-21 0:03

OriginalGriff wrote:
a bald statement like "WHERE only works with SELECT" is not accurate and can confuse.

Would that be a statement without any hair? Big Grin | :-D

The difficult we do right away...
...the impossible takes slightly longer.

OriginalGriff10-Jul-21 0:10

10-Jul-21 0:10

Wouldn't know - I still have a ponytail. Big Grin | :-D

How to create Shared memory between C# application and VC++ console application

SeeSharp212-Jul-21 1:11

SeeSharp2

12-Jul-21 1:11

For inserting data. Stay in context. D'Oh! | :doh:

manoharbalu8-Jul-21 1:46

manoharbalu

8-Jul-21 1:46

I want to create shared memory in a C# windows application. And a second console application in visual studio has to share the same memory using OpenFileMapping function.

Is it possible to share memory as I mentioned between one application in C# and other application in Visual C++ console application.

Please advise and suggest the ways of doing this

Re: How to create Shared memory between C# application and VC++ console application

Richard Deeming8-Jul-21 2:18

Richard Deeming

8-Jul-21 2:18

The BCL has plenty of support for memory-mapped files:
Memory-Mapped Files | Microsoft Docs[^]

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

Re: How to create Shared memory between C# application and VC++ console application

manoharbalu9-Jul-21 0:21

manoharbalu

9-Jul-21 0:21

This gives details for creating and opening shared memory between 2 C# application processes.

Please help me to share memory between 2 applications, one in C# and other VC++ console application to open the share memory created in C# application. Is it possible of doing this? Please advise

Re: How to create Shared memory between C# application and VC++ console application

Richard Deeming9-Jul-21 0:44

Richard Deeming

9-Jul-21 0:44

The documentation tells you how to create or access memory-mapped files from a C# application.

You presumably already know how to create or access memory-mapped files from a C++ application. If not, the Microsoft docs site has details:
Memory-Mapped File Information - Win32 apps | Microsoft Docs[^]

The file doesn't care which language was used to create the process that's accessing it.

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

Re: How to create Shared memory between C# application and VC++ console application

OriginalGriff8-Jul-21 2:20

Re: How to create Shared memory between C# application and VC++ console application

8-Jul-21 2:20

I would strongly suggest that you don't: instead redesign to use message based communications via Named Pipes[^] or Sockets C#[^] / Sockets C++[^]

It's a much more robust solution that can be a whole load more flexible.

Gerry Schmitz8-Jul-21 6:49

Gerry Schmitz

8-Jul-21 6:49

Going in circles.

Shared memory - C# Discussion Boards

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

Re: How to create Shared memory between C# application and VC++ console application

manoharbalu9-Jul-21 0:17

manoharbalu

9-Jul-21 0:17

But I didnt get a solution.

Please provide me some details and hints how to share memory between C# application and VC++ console application

Re: How to create Shared memory between C# application and VC++ console application

Gerry Schmitz9-Jul-21 5:39

Gerry Schmitz

9-Jul-21 5:39

You're stuck on one approach and not open to suggestions.

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

Re: How to create Shared memory between C# application and VC++ console application

jschell17-Jul-21 10:54

jschell

17-Jul-21 10:54

If helps.

A memory mapped file is an OS supported option.
C++ can use and access a memory mapped file.
C# can use and access a memory mapped file.

So the solution is
1. Study memory mapped files so you specifically understand how they can be shared between applications. I believe sharing requires a specific set up.
2. Study the api for C++ memory mapped files.
3. Study the api for C# memory mapped files.
4. Design how the memory mapped file will be used. Pay attention to failure scenarios.
5. Use 2 and 4 to implement a solution in the C++ app.
6. Use 3 and 4 to implement a solution in the C# app.

How to read value of a cell in GridView (DevExpress)?

Alex Dunlop7-Jul-21 5:18

Re: How to read value of a cell in GridView (DevExpress)?

7-Jul-21 5:18

Hi,
I searched DevExpress forum. They say that I need to use gridView.GetRowCellValue() method.
I used this code:

private void gridView4_DoubleClick(object sender, EventArgs e)
        {
            DXMouseEventArgs mouseEvent = e as DXMouseEventArgs;
            GridView view = sender as GridView;
            GridHitInfo info = view.CalcHitInfo(mouseEvent.Location);
            if (info.InRow || info.InRowCell)
            {
                MessageBox.Show(gridView4.GetRowCellValue(info.RowHandle, "File Name").ToString());
               
            }
        }

But I have error in MessageBox.... line.
it says:
System.NullReferenceException: 'Object reference not set to an instance of an object.'

DevExpress.XtraGrid.Views.Base.ColumnView.GetRowCellValue(...) returned null.

Richard MacCutchan7-Jul-21 5:39

Richard MacCutchan

7-Jul-21 5:39

Either your RowHandle or column name is invalid. Use the debugger to find out which, and why.

Re: How to read value of a cell in GridView (DevExpress)?

Alex Dunlop7-Jul-21 6:06