Question

There is a code

for j := 0 to mForm.ComponentCount - 1 do
    if mForm.Components[j] is TableFormInfo then
      //try
        //table := nil;
        //tempFmtable := nil;
        //tForm := nil;

        tForm := mForm.Components[j] as TableFormInfo;

        table := TTableSpec(DBSchema.Tables.FindComponent(tForm.Table));
        tempFmtable := TfmTableData.Create(MainWindow);
        tempFmtable.Name := tForm.Name;
        tempFmtable.tname := tForm.Table;
        //tempFmtable.Caption := Utf8ToAnsi(table.Description);
        tempFmtable.Left := tForm.LeftValue;
        tempFmtable.Top := tForm.TopValue;
        tempFmtable.Height := tForm.HeightValue;
        tempFmtable.Width := tForm.WidthValue;

        tempFmTable.IBQuery1.SQL.Clear;
        tempFmtable.IBQuery1.SQL.Add('select * from ' + table.Name);
        tempFmtable.IBQuery1.Open;
        tempFmtable.DragKind:=dkDock;
        tempFmtable.DragMode:=dmAutomatic;

        i := 0;
        querystr:='select ';
        while i <= tForm.ComponentCount - 1 do
          begin
          if tForm.Components[i] is TableFieldInfo then
          begin
            //querystr:='select ';
            //field := nil;
            //tempFmtable.Show;
            field := tForm.Components[i] as TableFieldInfo;
            tempFmtable.Caption:=tForm.Caption;
            tempFmtable.DBGrid1.Columns[i].FieldName := field.FieldNameValue;
            tempFmtable.DBGrid1.Columns[i].Title.Caption := field.DescriptionValue;
            tempFmtable.DBGrid1.Columns[i].Index := field.IndexValue;
            tempFmtable.DBGrid1.Columns[i].Visible := field.VisibleValue;
            tempFmtable.DBGrid1.Columns[i].Width:=field.WidthValue;
            //tempFmtable.CheckListBox1.Items.Add(field.Description);
            //tempFmtable.CheckListBox1.Checked[i] := field.Visible;
            //tempFmtable.Show;
             if field.VisibleValue  then querystr:=querystr+ConvertNameField(field.FieldNameValue)+', ';
          end;
            //inc(i);
          if tForm.Components[i] is SettingsFormInfo then
            begin
              //sForm:=nil;
              sForm:=tForm.Components[i] as SettingsFormInfo;
              tempsettings := TfmSettings.Create(tempFmtable);
              tempsettings.Caption:=sForm.Caption;
              //tempsettings := TfmSettings.Create(tempFmtable);
              tempsettings.Name := sForm.Name;
              tempsettings.Left := sForm.LeftValue;
              tempsettings.Top := sForm.TopValue;
              tempsettings.Height := sForm.HeightValue;
              tempsettings.Width := sForm.WidthValue;
              tempSettings.CheckListBox1.Clear;
              //for k:=0 to sForm.ComponentCount-1 do
              k:=0;
              while k<=sForm.ComponentCount-1 do
                begin
                  if sForm.Components[k] is ItemCheckListBoxInfo then
                    begin
                      //item:=nil;
                      item:=sForm.Components[k] as ItemCheckListBoxInfo;
                      tempsettings.CheckListBox1.Items.Add(item.TextValue);
                      tempsettings.CheckListBox1.Checked[item.IndexValue]:=item.CheckedValue
                    end;
                  if sForm.Components[k] is LabelInfo then
                    begin
                      //labelobj:=nil;
                      labelobj:=sForm.Components[k] as LabelInfo;
                      tempsettings.Label1.Caption:=labelobj.CaptionValue;
                    end;
                  if sForm.Components[k] is EditInfo then
                    begin
                      //edit:=nil;
                      edit:=sForm.Components[k] as EditInfo;
                      TEdit(tempsettings.FindComponent(edit.Name)).Text:=edit.TextValue;
                    end;
                    inc(k);
                end;
             if ((tForm.Components[i] is SettingsFormInfo) and (i=tForm.ComponentCount-1) and (k=sForm.ComponentCount)) then tempsettings.Show;
            end;
             //inc(i);
             //if ((tForm.Components[i] is SettingsFormInfo) and (i=tForm.ComponentCount-1) and (k=sForm.ComponentCount)) then tempsettings.Show;
             inc(i);
          end;

        {for i := 0 to table.Fields.ComponentCount - 1 do
        begin
          descr := Utf8ToAnsi(((table.Fields.Components[i]) as TFieldSpec).Description);
          tempFmtable.CheckListBox1.Items.Add(descr);
          tempFmtable.DBGrid1.Columns[i].Title.Caption := descr;
          tempFmtable.CheckListBox1.Checked[i] := true;
        end; }

        Delete(querystr, Length(querystr)-1, 1);
        querystr:=querystr+'from '+table.Name;
        tempFmTable.IBQuery1.SQL.Clear;
        tempFmtable.IBQuery1.SQL.Add(querystr);
        tempFmtable.IBQuery1.Open;
        for s := 0 to tForm.ComponentCount-1 do
          begin
            if tForm.Components[s] is TableFieldInfo then
              begin
                //field := nil;
                //tempFmtable.Show;
                field := tForm.Components[s] as TableFieldInfo;
                if field.VisibleValue then
                   begin
                     for t := 0 to tempFmtable.DBGrid1.Columns.Count-1 do
                       begin
                       if ((tempFmTable.DBGrid1.Columns[t].Title.Caption=field.DescriptionValue) and (tempFmtable.DBGrid1.Columns[t].FieldName=field.FieldNameValue)) then
                           tempFmTable.DBGrid1.Columns[t].Width:=field.WidthValue;
                       end;
                   end;
              end;
          end;
        tempFmtable.Show;

getting into condition by means of deserialization. I want to mark that before tForm variable use in line

table := TTableSpec(DBSchema.Tables.FindComponent(tForm.Table));

it is initialized in the previous line

tForm := mForm.Components[j] as TableFormInfo;

But despite this warning occurs during assembly

[dcc32 Warning] SerAndDeser.pas(298): W1036 Variable 'tForm' might not have been initialized

Why? How to get rid of the warning, without losing the functionality of the application?

Answer 1

Your indentation is all awry. I think this is what is confusing you. If you indent the code properly, it looks like this:

for j := 0 to mForm.ComponentCount - 1 do
  if mForm.Components[j] is TableFormInfo then
    // try
    // table := nil;
    // tempFmtable := nil;
    // tForm := nil;

    tForm := mForm.Components[j] as TableFormInfo;

table := TTableSpec(DBSchema.Tables.FindComponent(tForm.table));

I think it’s clear to see now that the code that follows the for loop can execute without tForm having been assigned.

It’s clear from the indentation in the question that you intended the long swathe of code that follows the assignment to be inside the if statement. But the compiler obeys the code rather than the indentation.

You are going to need to add some begin/end pairs to your code. Personally I never use the single statement syntax – all my blocks are compound blocks wrapped with begin/end pairs. In my view the single statement syntax is one of the great errors of Pascal. And indeed C.

I used the built-in code formatter to straighten out your indentation. That would probably be a useful tool that could help you to repair the code. And it could let you get a handle on how the indentation might be laid out correctly.

Finally, as I have said to you at least once before, do not use tForm as a variable name. This hides the type named TForm. The T prefix is reserved for types. You should call your form variable Form, or perhaps LForm with the L indicating that it is a local variable.