title: I need help in inno setup custom page
body: <p>In Inno Setup I have created a custom page with following code which has 3 text boxes.</p>
  
  <p>Now I want to validate that text box on custom form next button click. If in text.text='2121212' something text is entered by user then only next button enabled.</p>
  
  <pre><code>[CustomMessages]
  CustomForm_Caption=CustomForm Caption
  CustomForm_Description=CustomForm Description
  CustomForm_Label1_Caption0=College Name:
  CustomForm_Label2_Caption0=Product Type:
  CustomForm_Label3_Caption0=Product ID:
  
  [Code]
  var
    Label1: TLabel;
    Label2: TLabel;
    Label3: TLabel;
    Edit1: TEdit;
    Edit2: TEdit;
    Edit3: TEdit;
    Edit4: TEdit;
    Edit5: TEdit;
    Edit6: TEdit;
  
  { CustomForm_Activate }
  
  procedure CustomForm_Activate(Page: TWizardPage);
  begin
    // enter code here...
  
  
  end;
  
  { CustomForm_ShouldSkipPage }
  
  function CustomForm_ShouldSkipPage(Page: TWizardPage): Boolean;
  begin
    Result := False;
  end;
  
  { CustomForm_BackButtonClick }
  
  function CustomForm_BackButtonClick(Page: TWizardPage): Boolean;
  begin
    Result := True;
  end;
  
  { CustomForm_NextkButtonClick }
  
  function CustomForm_NextButtonClick(Page: TWizardPage): Boolean;
  begin
    RegWriteStringValue(HKEY_LOCAL_MACHINE, 'Software\SGS2.2\CS',
      'College Name', Edit1.Text);
     RegWriteStringValue(HKEY_LOCAL_MACHINE, 'Software\SGS2.2\CS',
      'Product Type', Edit2.Text);
      RegWriteStringValue(HKEY_LOCAL_MACHINE, 'Software\SGS2.2\CS',
      'Product ID', Edit3.Text);
    Result := True;
     end;
  
  { CustomForm_CancelButtonClick }
  
  procedure CustomForm_CancelButtonClick(Page: TWizardPage; var Cancel, Confirm: Boolean);
  begin
    // enter code here...
  end;
  
  { CustomForm_CreatePage }
  
  function CustomForm_CreatePage(PreviousPageId: Integer): Integer;
  var
    Page: TWizardPage;
  begin
    Page := CreateCustomPage(
      PreviousPageId,
      ExpandConstant('{cm:CustomForm_Caption}'),
      ExpandConstant('{cm:CustomForm_Description}')
    );
  
  { Label1 }
    Label1 := TLabel.Create(Page);
    with Label1 do
    begin
      Parent := Page.Surface;
      Caption := ExpandConstant('{cm:CustomForm_Label1_Caption0}');
      Left := ScaleX(16);
      Top := ScaleY(24);
      Width := ScaleX(70);
      Height := ScaleY(13);
    end;
  
    { Label2 }
    Label2 := TLabel.Create(Page);
    with Label2 do
    begin
      Parent := Page.Surface;
      Caption := ExpandConstant('{cm:CustomForm_Label2_Caption0}');
      Left := ScaleX(17);
      Top := ScaleY(56);
      Width := ScaleX(70);
      Height := ScaleY(13);
    end;
  
    { Label3 }
    Label3 := TLabel.Create(Page);
    with Label3 do
    begin
      Parent := Page.Surface;
      Caption := ExpandConstant('{cm:CustomForm_Label3_Caption0}');
      Left := ScaleX(17);
      Top := ScaleY(88);
      Width := ScaleX(70);
      Height := ScaleY(13);
    end;
  
    { Edit1 }
    Edit1 := TEdit.Create(Page);
    with Edit1 do
    begin
      Parent := Page.Surface;
      Left := ScaleX(115);
      Top := ScaleY(24);
      Width := ScaleX(273);
      Height := ScaleY(21);
      TabOrder := 0;
    end;
  
    { Edit2 }
    Edit2 := TEdit.Create(Page);
    with Edit2 do
    begin
      Parent := Page.Surface;
      Left := ScaleX(115);
      Top := ScaleY(56);
      Width := ScaleX(273);
      Height := ScaleY(21);
      TabOrder := 1;
    end;
  
    { Edit3 }
    Edit3 := TEdit.Create(Page);
    with Edit3 do
    begin
      Parent := Page.Surface;
      Left := ScaleX(115);
      Top := ScaleY(88);
      Width := ScaleX(273);
      Height := ScaleY(21);
      TabOrder := 2;
    end;
  
    with Page do
    begin
      OnActivate := @CustomForm_Activate;
      OnShouldSkipPage := @CustomForm_ShouldSkipPage;
      OnBackButtonClick := @CustomForm_BackButtonClick;
      OnNextButtonClick := @CustomForm_NextButtonClick;
      OnCancelButtonClick := @CustomForm_CancelButtonClick;
    end;
  
    Result := Page.ID;
  end;
  
  { CustomForm_InitializeWizard }
  
  procedure InitializeWizard();
  begin
  
    CustomForm_CreatePage(wpWelcome);
  
  end;
  </code></pre>