installation - Inno Setup Disable Next button when input is not valid

Question

I need to disable Next button, when input is not "Admin".

Something like:

procedure EditKeyPress(Sender: TObject; var Key: Char);
begin
  { enable the next button if the value in the box is admin; disable otherwise }
  WizardForm.NextButton.Enabled:=InputPage6.values[EditIndex2]??.Text = 'Admin'
end; 

Answer 1

Implement the input box OnChange event. You will also need to make sure the button state is updated, when the custom page is activated. You can use OnActivate event for that (or CurPageChanged event function).

var
  Page: TInputQueryWizardPage;

procedure ValidatePage;
begin
  WizardForm.NextButton.Enabled := (CompareText(Page.Values[0], 'Admin') = 0);
end;  

procedure EditChange(Sender: TObject);
begin
  ValidatePage;
end;

procedure PageActivate(Sender: TWizardPage);
begin
  ValidatePage;
end;

procedure InitializeWizard();
begin
  Page := CreateInputQueryPage(...);
  { To disable the Next button initially [when box is empty] }
  Page.OnActivate := @PageActivate;
  Page.Add(..., False);
  { Update Next button state on any input change (typing, copy&paste, whatever) }
  Page.Edits[0].OnChange := @EditChange;
end;

---

To combine multiple validations, see Inno Setup Disable Next button using multiple validation expressions (when input value matches one of multiple values).

For other approaches, see:

• Inno Setup - Create User Input Query Page with input length and format limit and use the input;
• Validate data on custom page when Next button is clicked in Inno Setup.