Question

I have a custom asp-net control that inherits from another one and its works as expected, though the properties are only set properly if i code them in the markup directly, so for instance if i need set a property at runtime that is some dynamic value, this value is never set or somehow lost.

Here’s the markup code:

<!--related form-->
<fw:advancedformdisplay id="formDisp" runat="server" captchaenabled="true" EmailEnabled="true" EnableViewState="true" captchaprivatekey="xxxxxxxxxxxxxxxxxxxx" captchapublickey="xxxxxxxxxxxxx" captchatheme="white" SourceType="MenuItem" SourceMainId="Auto">
</fw:advancedformdisplay> 

This is the code of the control:

    [DefaultProperty("CaptchaEnabled"),ToolboxData("<{0}:AdvancedFormDisplay runat=server></{0}:AdvancedFormDisplay>"), Description("This is an enhanced FormDisplay control that inlcudes Googles Captcha control is enabled")]
public class AdvancedFormDisplay :SiteBuilder.WebControls.FormDisplay
{
    bool _CaptchaEnabled = false, sendEmail = false;
    string captchaErrorMessage = "The verification code entered is not valid. Please try again!";
    RecaptchaControl captchaControl = null;
    string captchaPrivateKey = "", captchaPublicKey = "", captchaTheme = "clean";
    string originalFormHtml = string.Empty;
    string afterText = string.Empty, beforeText = string.Empty;
    Literal litHtmlForm = null;
    string captchaErrorClass = "errorCaptcha";

    public string EmailBeforeText
    {
        get { return beforeText; }
        set { beforeText = value; }
    }

    public string EmailAfterText
    {
        get { return afterText; }
        set { afterText = value; }
    }

    public string CaptchaErrorClass
    {
        get { return captchaErrorClass; }
        set { captchaErrorClass = value; }
    }

    public bool CaptchaEnabled
    {
        get { return _CaptchaEnabled; }
        set { _CaptchaEnabled = value; }
    }

    public bool EmailEnabled
    {
        get { return sendEmail; }
        set { sendEmail = value; }
    }

    public string CaptchaErrorMessage
    {
        get { return captchaErrorMessage; }
        set { captchaErrorMessage = value; }
    }

    /// <summary>
    /// red,white,blackglass,clean
    /// </summary>
    public string CaptchaTheme
    {
        get { return captchaTheme; }
        set { captchaTheme = value; }
    }

    public string CaptchaPrivateKey
    {
        get { return captchaPrivateKey; }
        set { captchaPrivateKey = value; }
    }

    public string CaptchaPublicKey
    {
        get { return captchaPublicKey; }
        set { captchaPublicKey = value; }
    }

    protected override void OnLoad(EventArgs e)
    {
        base.OnLoad(e);
    }


    public override void OnSaved(FormDisplayEventArgs e)
    {
        //If captcha control is enabled we need to adda  bit of code to redirect form properly
        if (CaptchaEnabled && e.Redirect && !e.SendMail)
        {
            //Do Stuff
        }

        if(sendEmail)
        {
            //Send email
        }

        base.OnSaved(e);
    }

    public override void OnSaving(FormDisplayEventArgs e)
    {
        if (CaptchaEnabled)
        {
            //Validate and do stuff
        }

        base.OnSaving(e);
    }
}

And then in my asp.net page that is using control, created by markup code, in the Page_Load() i try to assign some values to some properties and and the values aren’t set properly, meaning that if i have set for isntance, the property EmailBeforeText = “somthing” this value will not be assigned..

protected void Page_Load(object sender, EventArgs e)
{
    //2: Get the language of menuitem - Based on current culture setting (for by dropdownbox - change logic)
    try
    {
        currentCulture = Thread.CurrentThread.CurrentCulture.ToString();

        // Redirect if domain does not match rootnode.
        DomainChecker.CheckURL(this.Request, this.Response, currentCulture);

        if (footerArticle != null)
            footerArticle.SourceMenuId = Digimaker.Config.Custom.Get("FooterID_" + currentCulture).ToString();
    }
    catch
    {
        currentCulture = "en-GB";

        if( footerArticle != null )
            footerArticle.SourceMenuId = Digimaker.Config.Custom.Get("FooterID_" + currentCulture).ToString();
    }

Any ideas what i’m missing here?

Thanks a lot for your reading!

Regards,
byte_slave

Answer 1

short answer: use viewstate to persist your custom values!

• Understanding ASP.NET ViewState whitepaper (see example with NavigateUrl)

edit: as reading the white-paper is obviously a really hard thing:

Each control is responsible for storing its own state, which is
accomplished by adding its changed state to its ViewState property.
The ViewState property is defined in the System.Web.UI.Control class,
meaning that all ASP.NET server controls have this property available.
(When talking about view state in general I’ll use lower case letters
with a space between view and state; when discussing the ViewState
property, I’ll use the correct casing and code-formatted text.)

If you examine the simple properties of any ASP.NET server control
you’ll see that the properties read and write directly to the view
state. (You can view the decompiled source code for a .NET assembly by
using a tool like Reflector.) For example, consider the HyperLink Web
control’s NavigateUrl property. The code for this property looks like
so:

public string NavigateUrl
{
  get
  {
    string text = (string) ViewState["NavigateUrl"];
    if (text != null)
       return text;
    else
       return string.Empty;
  }
  set
  {
    ViewState["NavigateUrl"] = value;
  }
}

As this code sample illustrates, whenever a control’s property is
read, the control’s ViewState is consulted. If there is not an entry
in the ViewState, then the default value for the property is returned.
When the property is assigned, the assigned value is written directly
to the ViewState.