TdxBackendCustomParameters<T>.ParamByName Property

Returns the stored parameter with the specified name.

Declaration

property ParamByName[const AName: string]: T read; default;

Property Value

Type	Description
T	The parameter with the name matching the AName parameter value. If the collection contains no parameter with the name that matches the AName parameter value, an exception is thrown.

Remarks

Pass a parameter name to access the corresponding parameter in the collection of report / dashboard parameters.

To avoid an exception if the collection does not contain the target parameter, use the FindParam function. If you know the parameter’s index in the collection, use the Items property to access the target parameter.

Tip

ParamByName is the collection’s default property. You can omit its name and use only the parameter name in square brackets (for example, dxReportControl1.Parameters['ParameterName'] instead of dxReportControl1.Parameters.ParamByName['ParameterName']).

Code Examples

Note

The ParamByName property is common to report and dashboard parameters. These examples perform the same operation but use component-specific APIs.

Fetch Report Parameters by Name

Delphi

uses
  dxReport.Control,      // Declares the TdxReportControl class
  dxReport.Parameters,   // Declares the TdxReportParameter class
  dxMessageDialog;       // Declares the TdxMessageDialogForm class

procedure TForm1.cxButton1Click(Sender: TObject);
var
  ACountryParameter: TdxReportParameter;
  ADateParameter: TdxReportParameter;
begin
  // Fetch report parameters with specified names
  ACountryParameter := dxReportControl1.Parameters.ParamByName['countryParameter'];
  ADateParameter := dxReportControl1.Parameters['dateParameter'];
  // Display parameter labels
  dxShowMessageFmt('Parameter 1: %s' + #13#10 + 'Parameter 2: %s',
    [ACountryParameter.Description, ADateParameter.Description]);
end;

C++

#include "dxReport.Control.hpp"      // Declares the TdxReportControl class
#include "dxReport.Parameters.hpp"   // Declares the TdxReportParameter class
#include "dxMessageDialog.hpp"       // Declares the TdxMessageDialogForm class

// Add the following linker directives to the corresponding CPP source file:
#pragma link "dxReport.Control"   // Required to use dxReport.Control.hpp declarations

void __fastcall TForm1::cxButton1Click(TObject* Sender) {
  // Fetch report parameters with specified names
  TdxReportParameter* ACountryParameter = dxReportControl1->Parameters->ParamByName[L"countryParameter"];
  TdxReportParameter* ADateParameter = dxReportControl1->Parameters[L"dateParameter"];
  // Display parameter labels
  dxShowMessageFmt(L"Parameter 1: %s \n Parameter 2: %s",
    ARRAYOFCONST((ACountryParameter->Description, ADateParameter->Description)));
  }
}

Fetch Dashboard Parameters by Name

Delphi

uses
  dxDashboard.Control,      // Declares the TdxDashboardControl class
  dxDashboard.Parameters,   // Declares the TdxDashboardParameter class
  dxMessageDialog;       // Declares the TdxMessageDialogForm class

procedure TForm1.cxButton1Click(Sender: TObject);
var
  ACountryParameter: TdxDashboardParameter;
  AYearParameter: TdxDashboardParameter;
begin
  // Fetch dashboard parameters with specified names
  ACountryParameter := dxDashboardControl1.Parameters.ParamByName['countryParameter'];
  AYearParameter := dxDashboardControl1.Parameters['yearParameter'];
  // Display parameter labels
  dxShowMessageFmt('Parameter 1: %s' + #13#10 + 'Parameter 2: %s',
    [ACountryParameter.Description, AYearParameter.Description]);
end;

C++

#include "dxDashboard.Control.hpp"      // Declares the TdxDashboardControl class
#include "dxDashboard.Parameters.hpp"   // Declares the TdxDashboardParameter class
#include "dxMessageDialog.hpp"          // Declares the TdxMessageDialogForm class

// Add the following linker directives to the corresponding CPP source file:
#pragma link "dxDashboard.Control"   // Required to use dxDashboard.Control.hpp declarations

void __fastcall TForm1::cxButton1Click(TObject* Sender) {
  // Fetch report parameters with specified names
  TdxDashboardParameter* ACountryParameter = dxDashboardControl1->Parameters->
    ParamByName[L"countryParameter"];
  TdxDashboardParameter* AYearParameter = dxDashboardControl1->Parameters[L"yearParameter"];
  // Display parameter labels
  dxShowMessageFmt(L"Parameter 1: %s \n Parameter 2: %s",
    ARRAYOFCONST((ACountryParameter->Description, AYearParameter->Description)));
  }
}