在Delphi中使用FDMemtable时，如何正确证明DBGrid标题的合理性？

Question

I can't seem to get the fixed row Titles in a DBGrid to align right justified when using a FDMemtable. Whenever I set the Field alignment to taRightJustify it right justifies the data cells perfectly. However, the DBGrid titles are always left justified.

What's even more frustrating is I can set the corresponding DBGrid column title alignment to taRightJustify and it appears perfectly fine in the IDE. But when I run the program the column title shows as left justified.

Has anyone found a way to make DBGrid column titles stay right justified when using a FDMemtable?

BTW, this also happens with taCenter. The data cells align centered but the titles stay left justified.

PEBKAC

The issue was of my own making. I did not invoke the DBGrid Columns Editor and add all the fields. Instead, I was using the "Structure" pane and getting to the DBGrid columns that way. Although the Structure pane allowed me to modify the column titles this was only temporary and did not persist when the program was run.

Answer 1

The code below works for me in Seattle. I'm using a TClientDataSet rather than a TFDMemTable, but I can't see that that would make any difference.

If you have persistent columns defined on your DBGrid, you can also set a column's title alignment via the Object Inspector - use it to select the column, then expand its Title node and you can set the title alignment there.

procedure TForm1.CDS1AfterOpen(DataSet: TDataSet);
var
  i : Integer;
begin
  for i := 0 to DBGrid1.Columns.Count - 1 do
    DBGrid1.Columns[i].Title.Alignment := taRightJustify;
end;

Btw, if you think you're setting the alignment in the OI but it's getting ignored, see if you can find out why, as follows:

• Make sure your form is saved, then right-click on it and select View as text . Then, in the IDE editor window, you can see whether the Alignment property is saved as you've specified in the OI. Use the editor context menu to return to viewing the form as a form.

• Add an override of the form's Loaded method as I've described in a comment. With a breakpoint on the inherited in Loaded s body, you can inspect the Alignment value before and after inherited is called.

Why am I suggesting looking into Loaded ? Well, it is called after a form is streamed in from the DFM and is the routine where the run-time system finishes setting up the form. Sometimes, admittedly very rarely, another component (usually a 3rd-party one) misbehaves and causes strange behaviour of the properties of other compononents.

Answer 2

I can't reproduce the issue using a TFDMemTable either.

I dropped a TFDMemTable , TDataSource , and TDBGrid on a new VCL application's main form, connected them as usual (the grid's datasource set to DataSource1 , the datasource's DataSet set to FDMemTable1 ), and then added the below code to the form's OnCreate event:

procedure TForm3.FormCreate(Sender: TObject);
begin
  FDMemTable1.FieldDefs.Add('ID', ftInteger, 0, True);
  FDMemTable1.FieldDefs.Add('LastName', ftString, 20);
  FDMemTable1.FieldDefs.Add('FirstName', ftString, 20);
  FDMemTable1.FieldDefs.Add('Salary', ftCurrency);
  FDMemTable1.CreateDataSet;
  FDMemTable1.Active := True;
  FDMemTable1.AppendRecord([1, 'Smith', 'John', 30000]);
  FDMemTable1.AppendRecord([2, 'Jones', 'Jane', 40000]);
  FDMemTable1.AppendRecord([3, 'Doe', 'David', 2500]);
  DBGrid1.Columns[3].Alignment := TAlignment.taRightJustify;
  DBGrid1.Columns[3].Title.Alignment := TAlignment.taRightJustify;
end;

It also works correctly if I set everything up at designtime. Repeat the same setup steps I used above, but instead of using the code, use the following steps:

1. Select FDMemTable1 in the Object Inspector. At the bottom of the OI, click the LoadFromFile link, and navigate to the BDS Samples data folder (by default, in C:\\Users\\Public\\Public Documents\\Embarcadero\\Studio\\17.0\\Samples\\Data) and select animals.fds . (No specific reason for choosing that one, except it has a numeric field we can use for testing.)

2. Right-click on the DBGrid, and choose Columns Editor , or click the ellipsis button on the DBGrid.Columns property in the Object Inspector. Right-click in the Columns Editor and choose Add all fields .

3. Select either the Size or Weight column, expand it's Title property, and set Alignment to taRightJustify .

4. Run the application. The column you modified in step #3 above has a right-aligned title. (Here I used the Size column.)