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arun_pk wrote: handling exception
Try.....Catch blocks
arun_pk wrote: logging
Write your own logging class to write out to a text file or integrate with the Windows Event Log using System.Diagnostics.EventLog
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arun_pk wrote: the best way of handling exception
Depends on business requirements and application.
However there is unlikely to be a single answer to that even within a single application.
arun_pk wrote: know the best way of ... logging
Depends on business requirements an application. And can also depend on your definition of "logging" as well.
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Hi all,
I have two DataGridViews on my form with similar data in each. I'd like to view the same section of both DataGridViews at the same time. In other words, if the scroll bars in one DataGridView is scrolled, I want to set the scroll bars for the other one accordingly.
I found this article which explains how to set scroll bars (using Interop) but I'm either doing something wrong or it's just not working for DataGridViews:
How to change scrollbars position in a multiline textbox[^]
Based on the referenced article, this is block of code I currently have in the Scroll() event handler for but it does nothing:
int orientation = 0;
switch (e.ScrollOrientation)
{
case ScrollOrientation.HorizontalScroll: orientation = 0; break;
case ScrollOrientation.VerticalScroll: orientation = 1; break;
}
SetScrollPos(dataGridView2.Handle, orientation, e.NewValue, true);
SendMessage(dataGridView2.Handle, EM_LINESCROLL, 0, e.NewValue);
Could anyone help me out here please?
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Hi,
I haven't done this, however:
1.
EM_LINESCROLL seems appropriate for a line-oriented Control, not for a Row/Column/Cell-oriented one. Not sure what would fit better.
2.
I would try first without native code. I suggest you look into the Scroll event and the FirstDisplayedCell, FirstDisplayedScrollingRowIndex, FirstDisplayedScrollingColumnIndex properties. You could get the row/column indexes from the one DGV and use those in scrolling the other DGV.
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Thanks, but no, it doesn't quite solve my problem.
1. Yes, I also wondered about EM_LINESCROLL and I also wasn't sure what else to use or even how to go about finding out.
2. I know of the FirstDisplayedCell, FirstDisplayedScrollingRowIndex and FirstDisplayedScrollingColumnIndex properties but they only scroll the DataGridView to integral positions that coincide with the start of the referenced cell, row or column.
Thanks though.
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Have you tried: inheriting from DataGridView (gives you access to VerticalScrollBar), and putting some sort of synchronisation on your class?
class MyGrid : DataGridView {
public static void Link(IEnumerable<MyGrid> grids){
foreach(MyGrid grid in grids)
grid.VerticalScrollBar.Scroll += (s,e) => HandleScroll(grids, e.NewValue);
}
static void HandleScroll(IEnumerable<MyGrid> grids, int value){
foreach(MyGrid grid in grids) grid.VerticalScrollBar.Value = value;
}
}
And call it like:
var grids = List<MyGrid>();
grids.Add(myFirstGrid);
grids.Add(mySecondGrid);
MyGrid.Link(grids);
... in your form's initialisation process.
(Note: I haven't tried this, just going on the documentation.)
Ed: I tried, and you do have to have the lists as type MyGrid, not DataGridView. So you will have to make the controls on your form MyGrids, too. Also, you might want to handle DataGridView.Scroll as well as the scrollbar's Scroll; I'm not sure when each one gets fired.
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What a beautiful solution, thanks. It doesn't work 100% though. It only synchronises the scrollbars but not the actual position of the grid inside the gridview. Any idea why that would be? It seems that by setting MyGrid.VerticalScrollBar.Value, it only updates the position of the scrollbar but does nothing to the body of the grid.
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Ah damn, I thought that setting Value would make the grid scroll. I guess it is hooked to the Scroll property and I don't see any way of externally forcing a scrollbar to fire that. You could probably send it a WM_SCROLL but if you need to resort to P/Invoke then you might as well do that directly on the grid – I'm trying to turn up a managed solution.
Another thing you can try using the same protected-uncovering hackery is to call grid.OnScroll (with a ScrollEventArgs preset to the offset you want). But I suspect all that will do is fire the DGV.Scroll event and not actually cause the visible region to change.
You might have to resort to synchronising rows with FirstDisplayedRow, which isn't ideal.
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Yes, I'm pretty sure calling OnScroll will just fire the event but not update the actual gridview client area.
I wouldn't mind resorting to synchronising the two grids based on FirstDisplayedScrollingRowIndex and FirstDisplayedScrollingColumnIndex if I had a way of forcing the grid to only scroll horizontally to integral values.
In fact, for vertical scrolling, this method of syncing the two grids works perfectly. It's the horizontal scrolling that's a problem because the grid of which the scrollbar is moved can be scrolled to a position where it starts on a partial column, yet the linked grid will be scrolled to the start of that column.
Do you know if there is a way I could enforce horizontal scrolling to also be limited to integral positions as is the case with vertical scrolling?
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According to the documentation, DataGridView.HorizontalScrollOffset[^] is read/write. So you should be able to synchronise that without even needing to inherit from the DGV, as it's a public property. Why the vertical equivalent is read-only I don't understand. But that should work for horizontal scrolling (as long as you don't allow the user to mess with the column widths).
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Excellent. Thanks for the help. That is exactly what I was looking for.
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how to send file from Windows-CE to PC Through Socket
(and from PC to Windows-CE)
can i get any sample C# code for this ?
thanks in advance
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If I remember right, Windows CE supports the .Net Compact Framework, and that includes System.Net and System.IO. So you can just use standard socket and file I/O code on both ends.
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I am writing a C# windows forms application. It is a MDI application with lots of seperate forms. They all need to get to tables within a DataSet. What is the best way to make this DataSet "Global" for all forms within the application ?
My main thought is to create a static class. Create a static method that returns the dataset. Is this good programming practise ???
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Your application should have a data model somewhere. Ignore the UI for the moment and think about the business logic and the data layer. Typically your main application class (this is often MainForm, though if one is being strict it shouldn't be) will have a reference to a data model – for a simple application this might just be the data set.
Any UI views that refer to the data model should then be given a reference to it, possibly via a view-model (or presenter or similar) class if the binding process is more complex than being a direct editor of some part of the data model. Anything more than simple updates should be done with logic in the model layer, which is why you may need to write a class instead of just using a data set.
So the short answer is, put it in your main form class or your application class, if you have one, and pass a reference to it to the MDI children when they are created. But I would like you to understand why that is a good idea and how to extend it to more complex view/model situations.
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Hi,
I'm using the below code to search for a string(text) in Description using Lucene.Net. Its working fine. But when text has "-"(hyphen), its not returning the results. the length becomes zero. Could you let me know how to rectify this. Thanks in advance.
QueryParser parser = new QueryParser(Lucene.Net.Util.Version.LUCENE_29, "Description",
new WhitespaceAnalyzer());
Query qryDesc = parser.Parse("Description" + ":" + text + "*");
boolQuery.Add(qryLevel, BooleanClause.Occur.MUST);
TopDocs hits = searcher.Search(boolQuery, 10);
int length = hits.scoreDocs.GetLength();
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Lucene breaks up words on hyphens
see this for details
Its the man, not the machine - Chuck Yeager
If at first you don't succeed... get a better publicist
If the final destination is death, then we should enjoy every second of the journey.
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What is the best precise method of converting bit(0 or 1) from sql(row array text cell) to boolean value.
Thanks. If possible one line of code
I only read newbie introductory dummy books.
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It depends on the content of your text cell. If it's a single digit value ('0' or '1') then you can use Int32.Parse(), if it's some other text (e.g. "True", 'T', etc) then you will need to write your own conversion.
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Thank you. it is a single digit value from bit type sql.
Do you mean bool b = (bool)(Int32.Parse(row.cells[0].Text))
I only read newbie introductory dummy books.
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5fingers wrote: Do you mean bool b = (bool)(Int32.Parse(row.cells[0].Text))
That should do it.
5fingers wrote: I only read newbie introductory dummy books.
Time to move on to some serious reading then.
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No it does not.
bool b = (bool)(Int32.Parse(row.cells[0].Text))
Bind a gridview from a dataset with one column "status" being bit from sql table.
Then retrieve the value from gridviewrow cell. It returns an empty string. A VS2010 bug?
I only read newbie introductory dummy books.
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5fingers wrote: A VS2010 bug?
No, you're doing something wrong.
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1. create table test(name varchar(20),status bit not null)
assume status has value 0 or 1. then fill to a dataset.
Bind a gridview directly to dataset.
Column status shows true or false on gridview which is ok.
To retrieve the status value from gridviewrow.cells[1].text return empty string.
Confirm.
I only read newbie introductory dummy books.
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DataGridViews will return an empty string from a cell which has a null value (i.e. DBNull.Value). These cells will show as empty in the visible grid, too.
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