I would like to set the StartNewPage property of my child band from code based on some data from my database. I am using this to force a pagebreak if it is needed. If I try to modify this property in the OnBeforePrint event, it seems to ignore it on the first page of every report, then it starts to work on pages after that. Is there any way to set that property even sooner than OnBeforePrint? I am using FastReport 5.0.
Set child band's StartNewPage property when main band (TfrxMasterData for example) is printed
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I have a TStackPanel which I want to add a number of frames into at runtime. The number may vary each time the form is opened.
There seems to be limited information about TStackPanel around, and the examples I can find are in languages other than Delphi.
I have a loop that creates the frame, gives it a unique name and then adds it to the TStackPanel:
for i := 0 to 10 do
begin
mfSubFrame[i] := TMyFrame.Create(Application);
mfSubFrame.Name := name_array[i];
StackPanel1.InsertComponent(mfSubFrame[i]);
end;
This does not put anything in the stack panel. If I change the SP line to:
StackPanel1.InsertControl(mfSubFrame[i]);
then I do get a frame in the SP. It is the last one of the loop as I can tell by the name, the others may be hidden behind it but I can't tell. They are certainly not stacked horizontally like they should.
I have tried various other things like setting the parent of the frames to be the SP, and had a look at things like:
StackPanel1.Components.InsertComponent(mfSubFrame[i]);
and other sub-methods, but had no luck so far.
I suspect it may require a combination of statements, like add a control item as well as the actual component, but as I am working on the basis of trial and error it could be a long time before I stumble on the right combination.
I have never used the TStackPanel before, but it seems like you can add controls to it exactly the same way you add controls to any other windowed control: just create the control and assign its Parent.
For example,
for var i := 1 to 10 do
begin
var Memo := TMemo.Create(Self);
Memo.Parent := StackPanel1;
end;
will add ten memo controls (all owned by Self) to StackPanel1. There is no need to name the controls; referring to components by string name at runtime is an antipattern. (So is using FindComponent.)
InsertComponent() changes a component's Owner, which has no effect on visual display. You are creating each frame with Application as its Owner, and then changing its Owner to StackPanel1. You should assign the desired Owner when calling the component's constructor.
InsertControl() changes a control's Parent, which does affect visual display. You are creating each frame without a Parent, and then changing its Parent to be StackPanel1. You should be using the actual Parent property, not calling InsertControl() directly.
That being said, TStackPanel has a ControlCollection property that you are not doing anything with. That collection manages the actual stacking.
If needed 1, for each frame, try calling StackPanel1.ControlCollection.Add(), and then assigning the frame to the TStackPanelCollectionItem.Control property.
1: I don't have the source code for TStackPanel to look at, but I suspect TStackPanel probably handles this automatically for UI controls dropped onto it at design-time, but you might need to perform it manually for controls that you create dynamically at runtime. I'm not sure.
I bought the TMS Component pack and want to hide some component properties from displaying in the object inspector.
I am using UnlistPublishedProperty to hide them.
It works most of the time. But for some reason e.g. Anchors or StyleSettings are still displayed.
I am calling it like this:
UnlistPublishedProperty(TAdvEdit, 'StyleElements');
The weird thing is that it works on 90% of properties and i can't figure out why it will not hide the other properties from the object inspector.
I could edit the source and comment out the line where it gets published from TCustomEdit but i am wondering why the method with UnlistPublishedProperty isn't working.
Thanks!
The properties you are trying to remove are inherited from a higher ancestor class. If you wish to use UnlistPublishedProperty to remove these particular properties, you'll have to remove them from the ancestor. However, that would apply to all controls, not just the one you're working on.
In addition to Jerry's answer; there is a solution for deleting properties from sub-components. The third part of my answer here demonstrates how to filter out properties of a sub-component of a custom component by registering a component PropertyEditor and overriding GetProperties to filter specific property names.
I'm looking for the correct way in order to remove a TChart and deallocate all the memory.
I am using Delphi2007 with the standard TeeChart 7
I create the TChart programmatically:
var parentform: TForm;
begin
newchart:= TChart.Create(parentform);
newchart.Parent:= parentform;
...
Then, I want to remove only the chart from the form (not closing the form itself), but I get only that the chart becomes blank and stays on the form:
newChart.FreeAllSeries;
FreeAndNil(newChart);
if I use
NewChart.Parent := nil,
I don't see the chart anymore, but I think the TChart object still exists (until the parentform is destroyed). Is there a specific method for doing this?
Thank you
The most straightforward way to get rid of a TChart control, or just about any control, for that matter, is to call Free on it:
newChart.Free;
You can call FreeAndNil instead if you wish. That has the same effect of calling Free, but also sets the variable's value to nil. That's useful if you later test the variable's value to detect whether you still have access to the control. If you never reference the variable again, then FreeAndNil doesn't get you much.
The control will automatically free the other things it owns, such as the series you manually freed with FreeAllSeries. You don't need to free them yourself.
Merely clearing the control's Parent property does not free the control. You can prove that by re-assigning the Parent property and watching as the control re-appears on the screen. That wouldn't happen if the control had ceased to exist.
If the control remains visible on the screen after you free it, then you have other problems. Maybe the parent control hasn't repainted itself properly. You might try calling Refresh on the parent control. You might also have multiple controls visible. After all, the question's code creates two chart controls, so maybe one of them is still visible, and you've mistaken it for the control you destroyed.
I have a Delphi 6 app with a TListBox control set to lbOwnerDrawVariable. At run-time I add a single string to the list box. I have event handlers for OnMeasureItem() and OnDrawItem() and I set breakpoints on the very first line of code in each event handler. However neither of them are ever called. Not once. Not even if I make an Explicit Refresh or Repaint call on the list box.
This is really basic stuff so what is it that I am doing wrong that could inhibit the calling of those event handlers and subsequently disrupting my owner draw code? The single string does show in the list box properly. I threw in an OnClick() event handler just to see if it worked and did.
The OnMeasureItem and OnDrawItem events are (indirectly) triggered in response to the WM_MEASUREITEM and WM_DRAWITEM messages from Windows. Make sure you do not have any message handlers in your app that are filtering out that message, or the VCL's internal CN_MEASUREITEM and CN_DRAWITEM messages.
It turns out the problem was due to a non-zero value in the Columns property of the TListBox I was using. I had been experimenting with using columns earlier before I converted over to owner-draw and had left the TListBox.Columns property with a non-zero value. Apparently a non-zero Columns property value inhibits the triggering of owner-draw related event triggering. Once I set that property back to zero OnMeasureItem() and OnDrawItem() started firing.
There's really very little that can go wrong here. If you set up a test app to try this out then it functions just as you would expect and the event handlers are called.
The most likely cause of the behaviour you report is if the items are added before the event handlers are assigned. This typically happens if the items are added at design time in the .dfm file. You say you are adding the items at runtime. Perhaps you are adding them too soon, before the event handlers are assigned. What happens if you add items in response to an event, e.g. a button click. Try that out because you can be sure then then the event handlers are assigned by that point.
If that doesn't help then clearly you have some code in your app that is interfering with the VCL code.
I had this same issue: my OnDrawItem event handler was not being called if the Columns property was non-zero. It turned out this was because the Style property was set to lbOwnerDrawVariable. Variable item height is not allowed in conjunction with multiple columns, presumably because the rows would not line up across the columns if the item heights were allowed to be different. Once the Style property was set to lbOwnerDrawFixed the OnDrawItem event handler was called as expected.
I had a similar problem with a csOwnerDrawVariable-style combobox not triggering the OnMeasureItem event. As David Heffernan suggested, the issue was that the items had been added to the list at design time. The work-around I ended up using was to add code to the FormCreate event handler to copy the design-time list to a temporary variable, then clear the list and add the items back. Kludgy but effective.
I have a TcxGrid which consists of a master TcxGridLevel and 2 child TcxGridLevels (all of which use a TcxGridDBTableView). I would like to hide one of the child levels depending on the value of the master level record values. How do I go about this?
Here is a link to DevExpress describing what you want:
https://www.devexpress.com/Support/Center/Question/Details/Q96738
But this has some disadvantages in my opinion. First it is quite slow with bigger datasets. Second it comes to "flicker" when your master level changes frequently and the grid has to be redrawn. Maybe it is possible to set a filter to your detail-dataset so the details are "empty" when your nmaster has the correct condition. There is a property in TcxGrid to hide empty detail-tabs automatically.
Somewhat out of context but in case the link goes dead again:
1) How can I trigger Level3 OnGetGridView, because Level3 View was not change as I was expected
The OnGetGridView event is raised only once when the detail is first expanded. After the event handler has been executed, the specified GridView’s clone is created and cached so that the event doesn't fire when expanding the same master record next times. If you need the event to be raised later, you can clear all detail clones by calling the master DataController’s ClearDetails method or ClearDetailLinkObject methods.
You can find this information in the "TcxGridLevel.OnGetGridView" topic of the ExpressQuantumGrid's documentation.
2) I am also changing Level2 and Level3 Caption for every Gridview that it showing, but the changing is not automatically, sometime the Detail View need to be close and open again to make the Caption change.
If we're not mistaken, you change the Level's Caption in its OnGetGridView event handler. If so, the new caption isn't applied immediately because painting of the corresponding element isn't completed. As a workaround, you can perform a "delayed" operation by posting a custom message. I've attached a sample project to illustrate this approach in action. Hopefully, it will serve your needs, and adapting it won't be aproblem.