Complete Examples

Complete Examples

Example 1: Customer Orders Report with Date Range

Data Setup:

qryCustomers:
  SQL: SELECT CustomerID, CompanyName FROM Customers ORDER BY CompanyName
  
qryOrders:
  SQL: SELECT * FROM Orders 
       WHERE CustomerID = :CustomerID 
         AND OrderDate BETWEEN :StartDate AND :EndDate

Dialog Layout:

Label1: "Customer:"
DBLookupComboBox1: (ListSource=dsCustomers, KeyField=CustomerID, ListField=CompanyName)

Label2: "Start Date:"
DateEdit1:

Label3: "End Date:"
DateEdit2:

btnOK: (ModalResult=mrOk)
btnCancel: (ModalResult=mrCancel)

Dialog Script:

procedure DialogPage1OnShow(Sender: TfrxComponent);
var
  ds: TfrxDataSet;
begin
  // Set default dates
  DateEdit2.Date := Date;
  DateEdit1.Date := Date - 30;
  
  // Set first customer
  ds := DBLookupComboBox1.ListSource.DataSet;
  if Assigned(ds) and (ds.RecordCount > 0) then
  begin
    ds.First;
    DBLookupComboBox1.KeyValue := ds.Value['CustomerID'];
  end;
end;

procedure DialogPage1OnCloseQuery(Sender: TfrxComponent; var CanClose: Boolean);
begin
  // Validate
  if VarIsNull(DBLookupComboBox1.KeyValue) then
  begin
    ShowMessage('Please select a customer');
    CanClose := False;
    Exit;
  end;
  
  if DateEdit1.Date > DateEdit2.Date then
  begin
    ShowMessage('Start date must be before end date');
    CanClose := False;
    Exit;
  end;
  
  // Set parameters
  qryOrders.Close;
  qryOrders.ParamByName('CustomerID').Value := DBLookupComboBox1.KeyValue;
  qryOrders.ParamByName('StartDate').Value := DateEdit1.Date;
  qryOrders.ParamByName('EndDate').Value := DateEdit2.Date;
  qryOrders.Open;
  
  CanClose := True;
end;

Example 2: Product Sales with Multiple Filters

Dialog Controls:

DBLookupComboBox1: Category selection
DBLookupComboBox2: Product selection
CheckBox1: Include inactive products
Edit1: Minimum quantity

Dialog Script:

procedure DialogPage1OnShow(Sender: TfrxComponent);
begin
  // Set defaults
  CheckBox1.Checked := False;
  Edit1.Text := '0';
  
  // Set first category
  var ds := DBLookupComboBox1.ListSource.DataSet;
  if Assigned(ds) and (ds.RecordCount > 0) then
  begin
    ds.First;
    DBLookupComboBox1.KeyValue := ds.Value['CategoryID'];
  end;
end;

procedure DBLookupComboBox1OnChange(Sender: TfrxComponent);
begin
  // When category changes, update product list
  qryProducts.Close;
  qryProducts.ParamByName('CategoryID').Value := DBLookupComboBox1.KeyValue;
  qryProducts.Open;
  
  // Select first product in new list
  if qryProducts.RecordCount > 0 then
  begin
    qryProducts.First;
    DBLookupComboBox2.KeyValue := qryProducts.Value['ProductID'];
  end;
end;

procedure DialogPage1OnCloseQuery(Sender: TfrxComponent; var CanClose: Boolean);
var
  MinQty: Integer;
begin
  // Validate numeric input
  try
    MinQty := StrToInt(Edit1.Text);
    if MinQty < 0 then
    begin
      ShowMessage('Minimum quantity cannot be negative');
      CanClose := False;
      Exit;
    end;
  except
    ShowMessage('Please enter a valid number');
    CanClose := False;
    Exit;
  end;
  
  // Set all parameters
  qrySales.Close;
  qrySales.ParamByName('ProductID').Value := DBLookupComboBox2.KeyValue;
  qrySales.ParamByName('IncludeInactive').Value := CheckBox1.Checked;
  qrySales.ParamByName('MinQty').Value := MinQty;
  qrySales.Open;
  
  CanClose := True;
end;

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