An example of ViewState in ASP.NET

One of an approach to save data for user is the ViewState. The ViewState allows ASP.NET to repopulate form fields on each postback to the server, making sure that a form is not automatically cleared when the user hits the submit button. All this happens automatically, unless you turn it off, but you can actually use the ViewState for your own purposes as well. Please keep in mind though, that while cookies and sessions can be accessed from all your pages on your website, ViewState values are not carried between pages. Here is a simple example of using the ViewState, the value entered will be save between postbacks

On the aspx file:

    <form id="form1" runat="server">
    <div>
        <asp:TextBox ID="txt1" runat="server"></asp:TextBox> 
        <asp:Label ID="lbl1" runat="server"></asp:Label>
        <asp:Button ID="btn1" runat="server" Text="ViewState" OnClick="btn1_click"/> <br />                         
    </div>
    </form>

On the code file:
protected void btn1_click(object sender, EventArgs e)
{
            string oldText = (string)ViewState["currentText"];
            string newText = oldText + " " + txt1.Text;
            //First, we assign this new value to the label
            lbl1.Text = newText;
            //Secondly, we replace the old value of the view state so that the new value is read the next //time
            ViewState["currentText"] = newText;
            txt1.Text = "";
}

Hope this helps!

Posted in: .NET, ViewState