View.Refresh(Boolean) Method

Refreshes displayed values of the View‘s controls with new values from the data source collection (and optionally, from the database itself).

Namespace: DevExpress.ExpressApp

Assembly: DevExpress.ExpressApp.v23.2.dll

NuGet Package: DevExpress.ExpressApp

Declaration

C#

public void Refresh(
    bool refreshDataSource
)

VB.NET

Public Sub Refresh(
    refreshDataSource As Boolean
)

Parameters

Name	Type	Description
refreshDataSource	Boolean	true, if the data source needs to be refreshed as well; otherwise, false.

Remarks

Use this method to manually refresh control values in the current View when displayed objects do not raise notifications on data changes themselves (e.g., when the object type does not support INotifyPropertyChanged, or when the data source does not support IBindingList).

The Refresh method calls View.RefreshDataSource when the refreshDataSource parameter is set to true.

The following example uses a Parametrized Action to search for a Person by LastName, and then assigns all deferred tasks to that person.

C#

using System.Collections.Generic;
using DevExpress.Data.Filtering;
using DevExpress.ExpressApp;
using DevExpress.ExpressApp.Actions;
using DevExpress.Persistent.Base;
using DevExpress.Persistent.Base.General;
using DevExpress.Persistent.BaseImpl;
using MainDemo.Module.BusinessObjects;
// ...
public class AssignTasksController : ViewController {
    public AssignTasksController() {
        TargetObjectType = typeof(DemoTask);
        ParametrizedAction assignTasksAction = new ParametrizedAction(
            this, "AssignTasks", PredefinedCategory.Edit, typeof(string));
        assignTasksAction.Execute += AssignTasksAction_Execute;
    }
    private void AssignTasksAction_Execute(object sender, ParametrizedActionExecuteEventArgs e) {
        using(IObjectSpace objectSpace = Application.CreateObjectSpace(typeof(Person))) { 
            string personParamValue = e.ParameterCurrentValue as string;
            Person person = objectSpace.FirstOrDefault<Person>(p => p.LastName.Contains(personParamValue));
            if(person != null) {
                CriteriaOperator taskCriteria = CriteriaOperator.Parse("[Status] = ?", TaskStatus.Deferred);
                IList<DemoTask> tasks = objectSpace.GetObjects<DemoTask>(taskCriteria);
                foreach(DemoTask task in tasks) {
                    task.AssignedTo = person;
                }
                objectSpace.CommitChanges();
            }
        }
        View.Refresh(true);
    }
}

VB.NET

Imports System.Collections.Generic
Imports DevExpress.Data.Filtering
Imports DevExpress.ExpressApp
Imports DevExpress.ExpressApp.Actions
Imports DevExpress.Persistent.Base
Imports DevExpress.Persistent.Base.General
Imports DevExpress.Persistent.BaseImpl
Imports MainDemo.Module.BusinessObjects

Public Class AssignTasksController
    Inherits ViewController
    Public Sub New()
        TargetObjectType = GetType(DemoTask)
        Dim assignTasksAction As New ParametrizedAction(Me, "AssignTasks", PredefinedCategory.Edit, GetType(String))
        AddHandler assignTasksAction.Execute, AddressOf AssignTasksAction_Execute
    End Sub
    Private Sub AssignTasksAction_Execute(ByVal sender As Object, ByVal e As ParametrizedActionExecuteEventArgs)
        Using objectSpace As IObjectSpace = Application.CreateObjectSpace(GetType(Person))
            Dim personParamValue As String = TryCast(e.ParameterCurrentValue, String)
            Dim person As Person = objectSpace.FirstOrDefault(Function (p as Person) p.LastName.Contains(personParamValue))
            If person IsNot Nothing Then
                Dim taskCriteria As CriteriaOperator = CriteriaOperator.Parse("[Status] = ?", TaskStatus.Deferred)
                Dim tasks As IList(Of DemoTask) = objectSpace.GetObjects(Of DemoTask)(taskCriteria)
                For Each task As DemoTask In tasks
                    task.AssignedTo = person
                Next task
                objectSpace.CommitChanges()
            End If
        End Using
        View.Refresh(True)
    End Sub
End Class