Re: horizontal Panel scrolling - unexpected behaviour - C# Discussion Boards

horizontal Panel scrolling - unexpected behaviour

lukeer13-Jan-10 22:29

13-Jan-10 22:29

Hi Experts,

I'd like to enable my MyPanel:System.Windows.Forms.Panel to
- scroll vertically on mouse wheel move
- scroll horizontally on [Shift] + mouse wheel move and
- zoom on [Ctrl] + mouse wheel move

Scrolling vertically is Panel's built-in functionality. It's enough to use

base.OnMouseWheel(e);

for that purpose.

To achieve horizontal scrolling I tried this one:

protected override void OnMouseWheel(MouseEventArgs e)
        {
            if ((Control.ModifierKeys & Keys.Shift) == Keys.Shift)
            {
                m_iMouseWheelDeltaAccumulator += e.Delta;
 
                int iHorizontalPosition = 0;
 
                while (
                    m_iMouseWheelDeltaAccumulator < -m_iMouseWheelDeltaThreshold
                    || m_iMouseWheelDeltaAccumulator > m_iMouseWheelDeltaThreshold
                )
                {
                    iHorizontalPosition = HorizontalScroll.Value;
 
                    if (m_iMouseWheelDeltaAccumulator < 0)
                    {
                        iHorizontalPosition -= m_iMouseWheelDeltaThreshold;
                        m_iMouseWheelDeltaAccumulator += m_iMouseWheelDeltaThreshold;
                    }
                    else if (m_iMouseWheelDeltaAccumulator > 0)
                    {
                        iHorizontalPosition += m_iMouseWheelDeltaThreshold;
                        m_iMouseWheelDeltaAccumulator -= m_iMouseWheelDeltaThreshold;
                    }
 
                    if (iHorizontalPosition < HorizontalScroll.Minimum)
                        iHorizontalPosition = HorizontalScroll.Minimum;
                    else if (iHorizontalPosition > HorizontalScroll.Maximum)
                        iHorizontalPosition = HorizontalScroll.Maximum;
 
                }
 
                HorizontalScroll.Value = iHorizontalPosition;
            }
        }

And it does work.

Nearly.

But there are two unexpected points:
- The movement of content and scroll bars differs.
- The panel doesn't scroll the same distance every time I scroll one mouse wheel step. The distance gets bigger at first. Then, after ten or so steps, it gets smaller for the same amount of steps. And then it gets bigger again. The scrolling distance seems to oscillate (without the negative alternation).

How do I achieve a "normal" behaviour, like in OpenOfficeOrg, for example?

Ciao,

luker

Re: horizontal Panel scrolling - unexpected behaviour

Covean13-Jan-10 23:07

Covean

13-Jan-10 23:07

I didn't understand your complete code but maybe thats the problem:

while (condition)
{
    iHorizontalPosition = HorizontalScroll.Value;
    ...
}
HorizontalScroll.Value = iHorizontalPosition;

Maybe you meant:

while (condition)
{
    iHorizontalPosition = HorizontalScroll.Value;
    ...
    HorizontalScroll.Value = iHorizontalPosition;
}

Because you recalulate iHorizontalPosition every while iteration but you also overwrites it in the next iteration.

Greetings
Covean

Re: horizontal Panel scrolling - unexpected behaviour

lukeer14-Jan-10 0:03

lukeer

14-Jan-10 0:03

Hello Covean,

this is indeed a mistake.

Both assignments should be either within or outside of the loop, not one inside and the other one outside.

But unfortunately, that doesn't solve my problem (see my first answer to the original post).

Ciao,

luker

Re: horizontal Panel scrolling - unexpected behaviour

Covean14-Jan-10 1:22

Covean

14-Jan-10 1:22

Tried to look for at the LargeChange / SmallChange value properties of HorizontalScroll?
Because one "step"/"delta" of my mouse wheel is +-120 and maybe this differs from the Large/SmallChange values.

Greetings
Covean

Re: horizontal Panel scrolling - unexpected behaviour

lukeer14-Jan-10 2:45

lukeer

14-Jan-10 2:45

The values for SmallChange (=5) and LargeChange (=995) don't seem to have anything to do with mouse wheel scrolling.
They are used for scrolling on mouse click or keyboard hit, IIRC. At least, my problem persists with both values set to 120, which equals MouseEventArgs.Delta on my system, too.

Ciao,

luker

Re: horizontal Panel scrolling - unexpected behaviour

Covean14-Jan-10 3:36

Covean

14-Jan-10 3:36

Last 3 ideas of mine:

1. Take a look at the 5 AutoScroll values of your panel.
2. I would look at every place where you access the scrollbar.
3. Set a conditional breakpoint (on change) at the scroll value to find out where the gets changed.

Hope this helps.

Greetings
Covean

Re: horizontal Panel scrolling - unexpected behaviour

lukeer13-Jan-10 23:57

lukeer

13-Jan-10 23:57

I'm afraid my code was not as clear as possible.

The behaviour I described is generated by this code, too:

protected override void OnMouseWheel(MouseEventArgs e)
{
    if ((Control.ModifierKeys & Keys.Shift) == Keys.Shift)
    {
        // Get original horizontal position
        int iHorizontalPosition = HorizontalScroll.Value;

        // Apply change to horizontal position
        iHorizontalPosition += e.Delta;

        // Consider range of HorizontalScroll.Value
        if (iHorizontalPosition < HorizontalScroll.Minimum)
            iHorizontalPosition = HorizontalScroll.Minimum;
        else if (iHorizontalPosition > HorizontalScroll.Maximum)
            iHorizontalPosition = HorizontalScroll.Maximum;

        // Use result to scroll panel
        HorizontalScroll.Value = iHorizontalPosition;
    }
}

What could cause the described behaviour?
And how do I scroll MyPanel horizontally in a satisfactory manner?

Ciao,

luker

Re: horizontal Panel scrolling - unexpected behaviour

lukeer14-Jan-10 3:13

lukeer

14-Jan-10 3:13

Hello again,

I did some testing. As you can see in this piece of code,

if ((Control.ModifierKeys & Keys.Shift) == Keys.Shift)
            {
                // Get original horizontal position
                int iHorizontalPosition = HorizontalScroll.Value;
                if (iHorizontalPosition != m_iSavedHorizontalPosition)
                {
                    ; // Set breakpoint here
                }

                // [..] // Horizontal scrolling position calculation

                // Use result to scroll panel
                HorizontalScroll.Value = iHorizontalPosition;

                // Remember horizontal scrolling position
                m_iSavedHorizontalPosition = iHorizontalPosition;
            }

the method remembers m_iSavedHorizontalPosition (a MyPanel member variable) after applying it to HorizontalScroll.Value. On the next call the method compares the saved member variable with the value of HorizontalScroll.Value.

They differ.

Do I have to call some "ApplyScrollSettings"-method on MyPanel for HorizontalScroll.Value to take effect?

Ciao,

luker

Application and Window's context menu

Islorvat13-Jan-10 21:11

Islorvat

13-Jan-10 21:11

Hello!

I am using the windows context menu. My problem is that when i select multiple files the application will open as many times as selected files.
In HKEY_CLASSES_ROOT\*\shell i have a key with the shortcut to my app and %1. Should the "%1" parameter be changed?
Using the "SendTo" and creating a shortcut to the application will work as i wish, but how can i make it work the same way "SendTo" works for the context menu?

I hope i made myself understood. I know this is more of a windows problem and not a C# one.

Thanks!

Re: Application and Window's context menu

Eddy Vluggen13-Jan-10 22:47

Eddy Vluggen

13-Jan-10 22:47

Islorvat wrote:
I am using the windows context menu. My problem is that when i select multiple files the application will open as many times as selected files.

Windows will launch a new process for each item, each process with a single parameter pointing to a file. You'd have to make sure that your application is launched just once, and collect the parameters from the other instances there.

This[^] article might help Smile | :)

I are Troll Suspicious | :suss:

Suppress Date on MS Report

kruegersck13-Jan-10 18:45

kruegersck

13-Jan-10 18:45

I have a date fields on my MS Report. If the date is blank or null, I do I suppress the date so It doesn't show 01/01/0001 on my report.

Thanks!

Re: Suppress Date on MS Report

loyal ginger14-Jan-10 5:20

loyal ginger

14-Jan-10 5:20

What you need to do is to tweak your query so that the date field shows whatever you want in the way you want. There are built-in functions for this.

Cancel CellValidating error in DataGridView, so can close form while invalid entry still present

Nigel Mackay13-Jan-10 18:31

Nigel Mackay

13-Jan-10 18:31

If the user has typed an invalid entry, so that CellValidating raises an error, and they then decide to abandon the edit and want to click the Cancel button, the form won't close because the eror still exists. Error needs to be cleared first.
I just can't work out a way to achieve that, short of teaching the user that if they click Cancel, and the form doesn't close, press Esc so text reverts to original and then click Cancel again. Not ideal. Smile | :)

Re: Cancel CellValidating error in DataGridView, so can close form while invalid entry still present

6,921,364 and growing24-Apr-11 20:19

6,921,364 and growing

24-Apr-11 20:19

I know it's pretty old but I faced the same problem and wanted to ask if you managed solve it or not?
Even setting CausesValidation property of the close button doesn't work. What have you done to work around the issue?

Thanks a lot.

Re: Cancel CellValidating error in DataGridView, so can close form while invalid entry still present

Nigel Mackay24-Apr-11 20:41

Nigel Mackay

24-Apr-11 20:41

As far as I can remember I didn't solve the problem. User must press Esc to cancel the edit before doing ANYTHING else. You notice no-one offered a solution.

Re: Cancel CellValidating error in DataGridView, so can close form while invalid entry still present

6,921,364 and growing27-Apr-11 3:43

6,921,364 and growing

27-Apr-11 3:43

Thanks for replying. I saw no one replied but thought you may have devised a work around.

The behaviour isn't good. Close button is close button afterall. Anyways thanks for your time.

Cheers!

Operation is not supported for this type of object

Abdul Rahman Hamidy13-Jan-10 18:09

Abdul Rahman Hamidy

13-Jan-10 18:09

Dear All,
I am using following statements to create a view [query] in Access 2003 but i am getting an error which states "Operation is not supported for this type of object"

query="create proc vw_getCommunityMember as SELECT CommunityMember.CommunityMemberID, CommunityMember.CommunityID, zPosition.PositionID, CommunityMember.MemberName, CommunityMember.Age, CommunityMember.FamilySize, CommunityMember.MemberName_Dari, zOccupation.Occupation, zLiteracyLevel.LiteracyLevel, zLeadershipCategory.LeadershipCategory, zIncomeStatus.IncomeStatus, zGender.Gender, zPosition.Position, CommunityMember.isSyn, CommunityMember.IncomeStatusID, CommunityMember.OccupationID, CommunityMember.GenderID, CommunityMember.LiteracyLevelID, CommunityMember.LeadershipCategoryID, IIf(IsNull([CommunityMember].[ElectionPeriod]),1,[CommunityMember].[ElectionPeriod]) AS ElectionPeriod FROM zPosition RIGHT JOIN (zOccupation RIGHT JOIN (zLiteracyLevel RIGHT JOIN (zLeadershipCategory RIGHT JOIN (zIncomeStatus RIGHT JOIN (zGender RIGHT JOIN CommunityMember ON zGender.GenderID = CommunityMember.GenderID) ON zIncomeStatus.IncomeStatusID = CommunityMember.IncomeStatusID) ON zLeadershipCategory.LeadershipCategoryID = CommunityMember.LeadershipCategoryID) ON zLiteracyLevel.LiteracyLevelID = CommunityMember.LiteracyLevelID) ON zOccupation.OccupationID = CommunityMember.OccupationID) ON zPosition.PositionID = CommunityMember.PositionID ORDER BY zPosition.PositionID;";
				cmd.CommandText=query;
				cmd.Connection=con;
				cmd.CommandType= CommandType.Text;
				cmd.Transaction=t;
				cmd.ExecuteNonQuery();

the error is not that much clear for me. any idea what the error states?

Abdul Rahaman Hamidy
Database Developer
Kabul, Afghanistan

Re: Operation is not supported for this type of object

SeMartens13-Jan-10 20:20

SeMartens

13-Jan-10 20:20

Hi,

are you sure that your statement is correct? I thought it must be "CREATE PROCEDURE". But more important is that the JET-Engine (which you propably use) does not support procedures. So take a look here:

http://office.microsoft.com/en-us/access/HP010322191033.aspx[^]

So you got several options:
1. Do not use a procedure (you are doing a simple select, right?)
2. Use another database which provides support for procedures (and a bigger amount of data)
3. Do not use the JET-Engine to create your procedure

Regards
Sebastian

It's not a bug, it's a feature!

Check out my CodeProject article Permission-by-aspect.

Me in Softwareland.

Re: Operation is not supported for this type of object

Abdul Rahman Hamidy13-Jan-10 20:26

Abdul Rahman Hamidy

13-Jan-10 20:26

thanks alot from your answer,
i sorted it out, there is a key word in my select statement, I used to put all Column names in brackets [] and now its working.

thanks, changing data provider is not the option.

Abdul Rahaman Hamidy
Database Developer
Kabul, Afghanistan

Desktop boundary

damianrda13-Jan-10 16:33

damianrda

13-Jan-10 16:33

Im trying to develop an app which is kind of like a smaller custom 'taskbar' i cant seem to find a way to shrink down the desktop area, essentially reserving 32 pixels from the top of the screen so maximized apps do not hide it/app does not hide app titlebar. Any suggestions would be greatly appreciated.

Re: Desktop boundary

Eddy Vluggen13-Jan-10 22:23

Eddy Vluggen

13-Jan-10 22:23

damianrda wrote:
Im trying to develop an app which is kind of like a smaller custom 'taskbar' i cant seem to find a way to shrink down the desktop area, essentially reserving 32 pixels from the top of the screen so maximized apps do not hide it/app does not hide app titlebar

Something like this[^]?

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Re: Desktop boundary

damianrda14-Jan-10 2:53

damianrda

14-Jan-10 2:53

Great, just what i was looking for... ty!

Re: Desktop boundary

Eddy Vluggen14-Jan-10 3:33

Eddy Vluggen

14-Jan-10 3:33

You're welcome Smile | :)