Access Div from one page to another using C# and VB.Net in ASP.Net

Refer:

1. [Solved] Access control from one page to another in ASP.Net

Else check this example. Now please take its reference and correct your code.

You can access PreviousPage if you have used Server.Transfer, not Response.Redirect. Since we can reference the PreviousPage and its controls using Server.Transfer.

Also in the main page set runat="server" for the div.

HTML

MainPage.aspx

<div id="dvDetails" runat="server">
    Test
</div>
<asp:Button ID="btnSubmit" Text="Submit" runat="server" OnClick="Submit" />

Incidencias.aspx

<asp:Label ID="Label1" runat="server" />

C#

MainPage.aspx.cs

protected void Submit(object sender, EventArgs e)
{
    Server.Transfer("Incidencias.aspx");
}

Incidencias.aspx.cs

protected void Page_Load(object sender, EventArgs e)
{
    if (Page.PreviousPage.FindControl("dvDetails") != null)
    {
        System.Web.UI.HtmlControls.HtmlGenericControl previousDiv = (System.Web.UI.HtmlControls.HtmlGenericControl)Page.PreviousPage.FindControl("dvDetails");
        Label1.Text = previousDiv.InnerText;
    }
}

VB.Net

MainPage.aspx.vb

Protected Sub Submit(ByVal sender As Object, ByVal e As EventArgs)
    Server.Transfer("Incidencias.aspx")
End Sub

Incidencias.aspx.vb

Protected Sub Page_Load(ByVal sender As Object, ByVal e As EventArgs) Handles Me.Load
    If Page.PreviousPage.FindControl("dvDetails") IsNot Nothing Then
        Dim previousDiv As System.Web.UI.HtmlControls.HtmlGenericControl = CType(Page.PreviousPage.FindControl("dvDetails"), System.Web.UI.HtmlControls.HtmlGenericControl)
        Label1.Text = previousDiv.InnerText
    End If
End Sub

Screenshot