How to: Pass a Hidden Dashboard Parameter to a Custom SQL Query in the WinForms Viewer

• Mar 31, 2018

The following example shows how to filter a custom SQL query by changing a parameter value in the DashboardViewer.CustomParameters event handler.

In this example, the custIDQueryParameter query parameter is included in a WHERE clause of a custom SQL query. The custIDQueryParameter parameter is also bound to the hidden custIDDashboardParameter dashboard parameter. The value of this parameter is changed at runtime by handling the DashboardViewer.CustomParameters event which is raised before the DashboardViewer sends a query to a database.

Note

A complete sample project is available at https://github.com/DevExpress-Examples/how-to-pass-a-hidden-dashboard-parameter-to-a-custom-sql-query-in-the-winforms-viewer-t338459.

Form1.cs

using DevExpress.DashboardCommon;
using System.Linq;

namespace Dashboard_CustomParameters_Win {
    public partial class Form1 : DevExpress.XtraEditors.XtraForm {
        public Form1() {
            InitializeComponent();

            dashboardViewer1.LoadDashboard(@"..\..\Data\Dashboard.xml");
        }

        private void dashboardViewer1_CustomParameters(object sender, CustomParametersEventArgs e) {
            var custIDParameter = e.Parameters.FirstOrDefault(p => p.Name == "custIDDashboardParameter");
            if (custIDParameter != null) {
                custIDParameter.Value = "AROUT";
            }
        }
    }
}

Form1.vb

Imports DevExpress.DashboardCommon
Imports System.Linq

Namespace Dashboard_CustomParameters_Win
    Partial Public Class Form1
        Inherits DevExpress.XtraEditors.XtraForm

        Public Sub New()
            InitializeComponent()

            dashboardViewer1.LoadDashboard("..\..\Data\Dashboard.xml")
        End Sub

        Private Sub dashboardViewer1_CustomParameters(ByVal sender As Object, ByVal e As CustomParametersEventArgs) _
            Handles dashboardViewer1.CustomParameters
            Dim custIDParameter = e.Parameters.FirstOrDefault(Function(p) p.Name = "custIDDashboardParameter")
            If custIDParameter IsNot Nothing Then
                custIDParameter.Value = "AROUT"
            End If
        End Sub
    End Class
End Namespace