TdxDashboardParameter Class

A dashboard parameter.

Declaration

TdxDashboardParameter = class(
    TdxBackendCustomParameter
)

Remarks

Dashboard parameters allow you and your end users to filter dashboard data dynamically. You can define a parameter and reference it in a dashboards query, filter criteria, or expressions (including calculated fields) at runtime instead of hard-coded values.

A TdxDashboardParameter object implements an individual parameter within a dashboard Parameters collection.

Main API Members

The following members allow you to configure dashboard parameters:

AllowNull

Specifies whether Null can be assigned as the dashboard parameter value.

DataType

Returns the parameter data type.

Description

Returns the parameter label displayed in the UI.

IsMultiValueParameter

Indicates if the parameter has multiple values.

Name

Returns the unique parameter identifier.

Value | Values

Specify the default parameter value.

Visible

Specifies whether the parameter editor is visible in the UI.

Code Examples

List Dashboard Parameters

Delphi

uses
  dxDashboard.Control,      // Declares the TdxDashboardControl class
  dxDashboard.Parameters,   // Declares the TdxDashboardParameter class
  dxMessageDialog,          // Declares the TdxMessageDialogForm class
  System.StrUtils;          // Provides advanced string management routines

procedure TForm1.cxButton1Click(Sender: TObject);
var
  AList: TStringList;
  AParameter: TdxDashboardParameter;
begin
  // Create a TStringList instance
  AList := TStringList.Create;
  try
    // Iterate through dashboard parameters
    for AParameter in dxDashboardControl1.Parameters do
      AList.Add(Format('- %s', [
        // Use the parameter Name if Description is missing
        IfThen(AParameter.Description <> '', AParameter.Description, AParameter.Name)
      ]));
    // Display the parameter list or a notification message if the list is empty
    if AList.Count > 0 then
      dxShowMessage(AList.Text)
    else
      dxShowMessage('The dashboard has no parameters.');
  finally
    AList.Free;
  end;
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) {
  TStringList* AList = new TStringList();
  try {
    // Iterate through dashboard parameters
    for (int i = 0; i < dxDashboardControl1->Parameters->Count; i++) {
      TdxDashboardParameter* AParameter = dxDashboardControl1->Parameters->Items[i];
      UnicodeString ALabel;
      // Use the parameter Name if Description is missing
      if (AParameter->Description.IsEmpty())
        ALabel = AParameter->Name;
      else
        ALabel = AParameter->Description;
      AList->Add(Format(L"- %s", ARRAYOFCONST((ALabel))));
    }
    // Display the parameter list or a notification message if the list is empty
    if (AList->Count > 0)
      dxShowMessage(AList->Text);
    else
      dxShowMessage(L"The dashboard has no parameters.");
  }
  __finally {
    delete AList;
  }
}

Related GitHub-Hosted Example Projects

View Example: Pass a Hidden Dashboard Parameter to a SQL Query

Direct TdxDashboardParameter Class References

The following public API members reference a TdxDashboardParameter object:

TdxDashboardParameters.FindParam

Returns the stored parameter with the specified name.

TdxDashboardParameters.Items

Provides indexed access to all parameters stored in the collection.

TdxDashboardParameters.ParamByName

Returns the stored parameter with the specified name.

Inheritance

TObject

TPersistent

TCollectionItem

TdxBackendCustomParameter

TdxDashboardParameter