I am new to Delphi creating runtime Tgrid and want to add some rows and columns. I googled but not getting any thing. i am at level zero. what i have tried i mentioned it below.This code is showing nothing on my form.
procedure TForm1.Button1Click(Sender: TObject);
var
Grid : TGrid;
begin
Grid := TGrid.Create(Form1);
Grid.Visible := True;
Grid.Margins.Left := 10;
Grid.Margins.Right := 10;
Grid.Margins.Top := 10;
Grid.Margins.Bottom := 10;
Grid.RowCount := 5;
end;
The grid control must have a parent control. Indeed, naturally, the system must know where (on the screen) to put your control!
You probably want the grid to have the form as its parent. If so, just add Grid.Parent := Form1; after the construction of the grid.
Of course, when you add this missing line of code and get to see the grid, you'll very soon notice that your Margins assignments have no effect. That's because by default you control the position of the control (no pun intended) manually using its Top, Left, Height, and Width properties.
But should you start experimenting with the Align property, you'll discover the effect of the margins, if you also set AlignWithMargins to True. For instance, if you set Align to alClient, the control will occupy all of its parent's client area, save the margins.
Related
I have an application which always starts initially maximized. This consists of putting Self.WindowState := wsMaximized; in the OnCreate of the main form.
Just before that, I'm assigning what should be the default dimensions of the main form, if the user were to change the window state to wsNormal.
So, in short, the main form's OnCreate handler looks something like:
procedure TfrmMain.FormCreate(Sender: TObject);
begin
Width:= 1300;
Height:= 800;
WindowState:= wsMaximized;
end;
Theoretically, I could assign these dimensions in design-time, and that does what I need. However, due to the size of my screen, and thus the IDE, the whole form is not visible at one glance without scrolling. In design, I keep the form size small, so I can see everything. But in runtime, I need to assign these default dimensions, and then maximize it by default. When the user changes the window state out of maximized, I expect it to go to those dimensions I dynamically assigned.
The issue is that it seems to lose those dimensions after maximizing the form, and it reverts back to whatever values were in design-time. If I comment out the line WindowState:= wsMaximized; then it shows the form in the desired default dimensions. However, maximizing it seems to overwrite and ignore these values I had just assigned before it.
How can I create and show my main form maximized by default, while at the same time dynamically assigning the default size, without my assigned values getting lost?
(Confirmed with 10.3.3.)
The exact origin of this problem I cannot pinpoint, but a reasonable cause would be that during the constructor the form component is being read and that previous sizes seem to be explicitly backed up:
procedure TControl.SetWidth(Value: Integer);
begin
SetBounds(FLeft, FTop, Value, FHeight);
Include(FScalingFlags, sfWidth);
if csReading in ComponentState then
FExplicitWidth := FWidth;
end;
A possible solution is to set the desired sizes in the OnCreate event, like you are doing now, but postpone setting the desired WindowsState until the OnShow event.
procedure TForm1.FormCreate(Sender: TObject);
begin
Width := 1300;
Height := 800;
end;
procedure TForm1.FormShow(Sender: TObject);
begin
WindowState := wsMaximized;
end;
Of course, you probably should prevent consecutive calls by using a one-off mechanism.
Please take a look at wsMaximized forms do not appear maximized too.
Apparently, the VCL does not store the explicit intermediate size (in some Delphi versions anyway) but seems to merge the change with that of the maximization when the form is actually shown.
Like Sertac Akyuz quite correctly suggested, you can use SetWindowPlacement to bypass this VCL interference:
procedure TForm1.FormCreate(Sender: TObject);
var
WindowPlacement: TWindowPlacement;
begin
GetWindowPlacement(Handle, WindowPlacement);
WindowPlacement.rcNormalPosition := Bounds(Left, Top, 1300, 800);
WindowPlacement.showCmd := SW_SHOWMAXIMIZED;
SetWindowPlacement(Handle, WindowPlacement);
end;
You must set form size on FormActivate:
procedure TfrmMain.FormActivate(Sender: TObject);
begin
if Tag = 0 then
begin
// Top := 100;
// Left := 100;
Width:= 1300;
Height:= 800;
WindowState:= wsMaximized;
Tag := 1;
end;
end;
is there any way, not that complicated to wrap the components of a FlowPanel for instance every 3 components?
as it works with the property autowrap but by a given amount of controls.
thanks in advance.
You left the actual image sizes open, so here its the general idea with some example sizes that you will have to adopt to your liking. I made some initial tests with buttons (normal width = 75), so I sized the TFlowPanel to 235 px wide.
The idea is to have a TFlowPanel with a fixed width (Constraints.MaxWidth = 235; Constraints.MinWidth = 235;) but AutoSize=True so it can grow downward. If you add e.g. 75px wide components, 3 of them fit perfectly on one row. If wider, only 2 or even only 1 fit on a row. So far as you wish. But if the width is only 56px (mean value) or less the number of compnents will be four or more.
I suggest a solution to place such a smaller component on a panel of its own, with a width of 75px, and that panel on the TFlowPanel. Thus no more than three components will fit on one row.
This is the code with which a number of buttons were placed on a TFlowPanel.
procedure TForm3.Button1Click(Sender: TObject);
var
btn: TButton;
pan: TPanel;
begin
inc(count);
btn := TButton.Create(self);
btn.Width := random(60)+35;
if btn.Width < 75 then
begin
pan := TPanel.Create(self);
pan.Width := 75;
pan.Height := 30;
pan.BevelOuter := bvNone;
btn.Parent := pan;
pan.Parent := FlowPanel1;
end
else
begin
btn.Parent := FlowPanel1;
end;
btn.Caption := IntToStr(count);
end;
And the end result
Alternative solution
Another solution (since you mentioned TImages) is to always create the TImages with a width of at least 75px. The picture (if smaller than that) can be centered in the TImage, if you like. This is based on the fact that the image doesn't affect the size of the TImage control (unless you want it to).
Also, if you don't really absolutely need to show the images in their full actual size, you can set the Proportional property true. From the docs:
When Proportional is true, images that are too large to fit in the image control are scaled down (while maintaining the same aspect ratio) until they fit in the image control.
I have a TDBRadioGroup that I've added to my form.
I'd really like to have the caption to the left of it instead of on top (the form's a little busy and tall, and I'm trying to squeeze it in).
I can add my own label to the left of the Radio Group. But the control insists on reserving space of a Caption that does not exists. Is there a way I can turn it off completely?
The best we've come up with so far is sticking it on a TPanel and then hiding the top couple lines off-panel.
A TGroupBox (and it's descendant TDBGroupBox) are basically wrappers around the Windows GroupBox. The control is designed to sport a user-defined label across the upper-left corner, and doesn't have any style setting to remove it.
So, short of creating your own control to host a series of TRadioButton controls yourself and display them, there's no built-in way to disable the space reserved for the caption. You can suppress the text, of course, by setting the Caption := '', but the padding for the text descenders is not removed simply because the caption isn't displayed.
You can override the paint procedure for TRadioGroup so that the frame is drawn closer to the top of your item list. You could create a new component of type TNoCaptionRadioGroup. You might still have to use the panel trick that you have tried, but by lowering the top of the frame you can grab the space consumed by the non-existent caption. Something like this:
tNoCaptionRadioBox = class(TRadioGroup)
protected
procedure paint; override;
end;
procedure tNoCaptionRadioBox.paint;
var
H: Integer;
R: TRect;
begin
with Canvas do
begin
Font := Self.Font;
H := TextHeight('0');
R := Rect(0, H, Width, Height);
if Ctl3D then
begin
Inc(R.Left);
Inc(R.Top);
Brush.Color := clBtnHighlight;
FrameRect(R);
OffsetRect(R, -1, -1);
Brush.Color := clBtnShadow;
end else
Brush.Color := clWindowFrame;
FrameRect(R);
end;
end;
This is taken from the code for painting a TCustomGroupBox. I have removed the code for drawing the caption and have changed the top of the frame to the full height of the Font. Your actual captioned radio buttons will still be drawn where Windows wants them to be and with the default spacing.
Remember to register the new component by running the package installation tool.
procedure Register;
begin
RegisterComponents('myComponents', [tNoCaptionRadioBox]);
end;
My form exceeds the window's height (when I use the splitter which changes a panel's height which in turn changes the form's size).
How can I stop it from resizing like that?
I assume you're changing the form size yourself, because I can't find a way to make the splitter do that automatically. You can get the Height of the screen using the Screen object in the Forms unit. You can simply test against Screen.Height or, if you want to better support multiple monitors, test against Screen.MonitorFromWindow(Handle).Height
Code sample, untested, should get you started:
var MaxFormHeight: Integer;
NewFormHeight: Integer;
M: TMonitor;
begin
// Get the monitor that's hosting the form
M := M := Screen.MonitorFromWindow(Handle);
MaxFormHeight := M.WorkAreaRect.Bottom - M.WorkAreaRect.Top - Top; // Take into account actual available monitor space and the Top of the window
// Do your stuff to calculate NewFormHeight
if NewFormHeight > MaxFormHeight then
NewFormHeight := MaxFormHeight;
Height := NewFormHeight;
end;
I need to find the entire size (also called "logical area") of a TScrollBox - as opposite to visible area that you get via Width and Height property (or ClientWidth ClientHeight).
I want to create some controls inside that TScrollBox. One of them (called TViewer) needs to be as high as the TScrollBox itself. The thing is that during creation, the TScrollBox is scrolled down to show last created control. So, using Top=1 will not work because my control will have top=1 which is not the top of the logical area.
Delphi 7
Drop a component, like a TLabel, on the TScrollBox.
Set the component's Left and Top properties to 0.
Set the component's Visible property to False.
Now you always have the origin. The "logical height" is now:
myScrollBox.Height + (myOriginControl.Top * -1);
Maybe ScrollBox.HorzScrollBar.Range and ScrollBox.VertScrollBar.Range + the corresponding .Positions are what you need.
Look at Scrollbars:
ScrollBox1.VertScrollBar.Range
ScrollBox1.HorzScrollBar.Range
It can be less than height and width if the scrollbox logical area is not bigger than phisical area (scrollbars not visible in that case)
Or use this to get the max of both:
var
AHeight, AWidth: Integer;
begin
AHeight := Max(ScrollBox1.VertScrollBar.Range, ScrollBox1.Height);
AWidth := Max(ScrollBox1.HorzScrollBar.Range, ScrollBox1.Width);
ShowMessageFmt('%d,%d', [AHeight, AWidth]);
end;
Edit
From #Altar comments, I can add the logical height and/or width is not the problem. If you want to add any control which occupies all the height of the scrollbar, use the AHeight from the above calculation, but set the Top to the negative of VertScrollBar.Position, something like this:
procedure TForm2.Button3Click(Sender: TObject);
var
AHeight, AWidth: Integer;
Btn: TButton;
begin
AHeight := Max(ScrollBox1.VertScrollBar.Range, Height);
AWidth := Max(ScrollBox1.HorzScrollBar.Range, Width);
Btn := TButton.Create(Self);
Btn.Parent := ScrollBox1;
Btn.Left := 15;
Btn.Top := -ScrollBox1.VertScrollBar.Position;
Btn.Height := AHeight;
end;
Im not sure i understand exactly what you want to do, but to get the complete area defined as "scrollable" you would have to write ScrollBox.HorScrollBar.Range + ScrollBox.Clientwidth (and the same thing for the vertical section). The scrollbox always deducts the visible "page" size from the total. So if you define a height of 1000 pixels, with 100 pixels showing - it will have a scrolling range of 900. You have to add the clientheight to get the rest.
Also, to get the correct "top" position you will have to read Canvas.Cliprect.Top, since a scrolling window does not change the top position of sub-controls. Windows handles this for you and only tells you what to re-draw once the scrollbars are initialized.
Since you want to create a control that is just as high as the complete scrollable area, i presume you are creating an editor of sorts?
If so you would probably get better results taking a look at SynEdit and extract the base-class that adds scrollbars to a normal TCustomControl (it's quite easy). That way you can control both the painting and the layout of your controls.
Here is one I wrote for Lazarus and FreePascal a while back. If you add messages to the uses clause and prefix the message handlers with WM rather than TLM it will compile under Delphi.
(code to long, had to use external link): http://delphimax.wordpress.com/2010/09/20/platform-independent-image-component-for-lazarus/
I have tried to do that, and believe me, I was not able to.
If you have the instances of the controls that are inside TScrollBox, you can use them to calculate (not precisely) the area.
Here is a complicated (but complete) solution:
I create my first child control during TScrollBox.Create (when TScrollBox does not have yet a scrollbar)
Set Child.Top:= 1
Create the rest of the child controls (this may force the TScrollBox to show the scrollbar)
Scroll the TScrollBox up
Use one of the above solutions to calculate the height of the TScrollBox