Keep ASP.Net TextBox Value while paging in GridView using C# and VB.Net

Hi imoleayoemman...,

You need to keep the data in DataTable. Then on TextBox change update the DataTable and use that DataTable to populate the GridView.

Refer below sample.

HTML

<asp:GridView runat="server" ID="gvOrders" AutoGenerateColumns="false"
    AllowPaging="true" PageSize="2" OnPageIndexChanging="OnPageIndexChanging">
    <Columns>
        <asp:BoundField DataField="Id" HeaderText="Id" />
        <asp:BoundField DataField="Item" HeaderText="Item" />
        <asp:BoundField DataField="Date" HeaderText="Date" />
        <asp:BoundField DataField="Amount" HeaderText="Amount" />
        <asp:TemplateField HeaderText="Amount Applied">
            <ItemTemplate>
                <asp:TextBox ID="txtAmountApplied" runat="server" Text='<%#Eval("AmountApplied") %>'
                    AutoPostBack="true" OnTextChanged="OnTextChanged" Width="100px" />
            </ItemTemplate>
        </asp:TemplateField>
    </Columns>
</asp:GridView>

Namespaces

C#

using System.Data;

VB.Net

Imports System.Data

Code

C#

protected void Page_Load(object sender, EventArgs e)
{
    if (!this.IsPostBack)
    {
        this.GetData();
        this.BindGridView();
    }
}

private void GetData()
{
    DataTable dt = new DataTable();
    dt.Columns.AddRange(new DataColumn[] {
        new DataColumn("Id"),
        new DataColumn("Item"),
        new DataColumn("Date"),
        new DataColumn("Amount"),
        new DataColumn("AmountApplied")
    });
    dt.Rows.Add(1, "T-Shirt", "07-09-2012", "595.46", "");
    dt.Rows.Add(2, "Pant", "07-09-2013", "48.29", "");
    dt.Rows.Add(3, "Football", "07-13-2013", "595.46", "");
    dt.Rows.Add(4, "Bat", "07-13-2013", "48.29", "");
    ViewState["Orders"] = dt;
}

private void BindGridView()
{
    gvOrders.DataSource = (DataTable)ViewState["Orders"];
    gvOrders.DataBind();
}

protected void OnTextChanged(object sender, EventArgs e)
{
    DataTable dt = (DataTable)ViewState["Orders"];
    GridViewRow row = (sender as TextBox).NamingContainer as GridViewRow;
    int id = Convert.ToInt32(row.Cells[0].Text);
    DataRow dr = dt.AsEnumerable().Where(x => Convert.ToInt32(x["Id"]) == id).FirstOrDefault();
    if (dr != null)
    {
        dr["AmountApplied"] = (sender as TextBox).Text;
    }
    ViewState["Orders"] = dt;
    this.BindGridView();
}

protected void OnPageIndexChanging(object sender, GridViewPageEventArgs e)
{
    gvOrders.PageIndex = e.NewPageIndex;
    this.BindGridView();
}

VB.Net

Protected Sub Page_Load(sender As Object, e As EventArgs) Handles Me.Load
    If Not Me.IsPostBack Then
        Me.GetData()
        Me.BindGridView()
    End If
End Sub

Private Sub GetData()
    Dim dt As DataTable = New DataTable()
    dt.Columns.AddRange(New DataColumn() {
                            New DataColumn("Id"),
                            New DataColumn("Item"),
                            New DataColumn("Date"),
                            New DataColumn("Amount"),
                            New DataColumn("AmountApplied")
                        })
    dt.Rows.Add(1, "T-Shirt", "07-09-2012", "595.46", "")
    dt.Rows.Add(2, "Pant", "07-09-2013", "48.29", "")
    dt.Rows.Add(3, "Football", "07-13-2013", "595.46", "")
    dt.Rows.Add(4, "Bat", "07-13-2013", "48.29", "")
    ViewState("Orders") = dt
End Sub

Private Sub BindGridView()
    gvOrders.DataSource = CType(ViewState("Orders"), DataTable)
    gvOrders.DataBind()
End Sub

Protected Sub OnTextChanged(sender As Object, e As EventArgs)
    Dim dt As DataTable = CType(ViewState("Orders"), DataTable)
    Dim row As GridViewRow = TryCast((TryCast(sender, TextBox)).NamingContainer, GridViewRow)
    Dim id As Integer = Convert.ToInt32(row.Cells(0).Text)
    Dim dr As DataRow = dt.AsEnumerable().Where(Function(x) Convert.ToInt32(x("Id")) = id).FirstOrDefault()

    If dr IsNot Nothing Then
        dr("AmountApplied") = (TryCast(sender, TextBox)).Text
    End If

    ViewState("Orders") = dt
    Me.BindGridView()
End Sub

Protected Sub OnPageIndexChanging(sender As Object, e As GridViewPageEventArgs)
    gvOrders.PageIndex = e.NewPageIndex
    Me.BindGridView()
End Sub

Screenshot