How to Change the PageCount at Runtime When Data Loaded on Demand is Filtered in WinForms DataPager?

This example illustrates how to change the PageCount at runtime when data loaded on demand is filtered in WinForms DataPager.

You can change the SfDataPager.PageCount at runtime based on the records count in on-demand paging. Here, PageCount are modified by filtering the records in run time.

C#

public partial class Form1 : Form
{
    Northwind northWind;
    List<Orders> source = new List<Orders>();

    public Form1()
    {
        InitializeComponent();
        string connectionString = string.Format(@"Data Source = {0}", ("Northwind.sdf"));
        //northWind dataProvider connectivity.
        northWind = new Northwind(connectionString);
        source = northWind.Orders.ToList();
        this.sfDataPager1.OnDemandLoading += OnDemandLoading;
    }

    private void OnDemandLoading(object sender, OnDemandLoadingEventArgs e)
    { 
        sfDataPager1.LoadDynamicData(e.StartRowIndex, source.Skip(e.StartRowIndex).Take(e.PageSize));
    }

    private List<Orders> ApplyFilter(Northwind NorthwindSource)
    {
        // records are filtered based on CustomerID column
        return NorthwindSource.Orders.Where(item => item.CustomerID.Contains(filterTextBox.Text)).ToList();
    }

    private void FilterBtn_Click(object sender, System.EventArgs e)
    {
        source = ApplyFilter(northWind);
        //page count resets based on filtered records.
        if (source.Count() < sfDataPager1.PageSize)
            this.sfDataPager1.PageCount = 1;
        else
        {
            var count = source.Count() / sfDataPager1.PageSize;
            if (source.Count() % sfDataPager1.PageSize == 0)
                this.sfDataPager1.PageCount = count;
            else
                this.sfDataPager1.PageCount = count + 1;
        }
        this.sfDataPager1.MoveToPage(0);
        this.sfDataPager1.Refresh();
    }

VB

Partial Public Class Form1
	Inherits Form
Private northWind As Northwind
Private source As New List(Of Orders)()

Public Sub New()
	InitializeComponent()
	Dim connectionString As String = String.Format("Data Source = {0}", ("Northwind.sdf"))
	'northWind dataProvider connectivity.
	northWind = New Northwind(connectionString)
	source = northWind.Orders.ToList()
	AddHandler Me.sfDataPager1.OnDemandLoading, AddressOf OnDemandLoading
End Sub

Private Sub OnDemandLoading(ByVal sender As Object, ByVal e As OnDemandLoadingEventArgs)
	sfDataPager1.LoadDynamicData(e.StartRowIndex, source.Skip(e.StartRowIndex).Take(e.PageSize))
End Sub

Private Function ApplyFilter(ByVal NorthwindSource As Northwind) As List(Of Orders)
	'records are filtered based on CustomerID column
	Return NorthwindSource.Orders.Where(Function(item) item.CustomerID.Contains(filterTextBox.Text)).ToList()
End Function

Private Sub FilterBtn_Click(ByVal sender As Object, ByVal e As System.EventArgs)
	source = ApplyFilter(northWind)
	'page count resets based on filtered records.
	If source.Count() < sfDataPager1.PageSize Then
		Me.sfDataPager1.PageCount = 1
	Else
		Dim count = source.Count() / sfDataPager1.PageSize
		If source.Count() Mod sfDataPager1.PageSize = 0 Then
			Me.sfDataPager1.PageCount = count
		Else
			Me.sfDataPager1.PageCount = count + 1
		End If
	End If
	Me.sfDataPager1.MoveToPage(0)
	Me.sfDataPager1.Refresh()
End Sub

Here, records are filtered based on the textbox text in clicking event of Filter button. Initially PageCount is 5 and it is changed as 1 once the records are filtered.