MVC server side validation with ASP.net - asp.net-mvc

Question

I am trying to put server side validation for a textbox in MVC website. Here is what I have:
<% using (Html.BeginForm("WebsiteLinks", "Home", FormMethod.Get))
{%>
<%: Html.ValidationSummary("Please enter valid URL and try again.") %>
<fieldset>
<p>
<%=Html.Label("Please enter URL:") %>
<%=Html.TextBox("url")%>
<%= Html.ValidationMessage("url", "*") %>
<input type="submit" value="Crawl" />
</p>
</fieldset>
<% } %>
And in the controller I have this:
public ActionResult WebsiteLinks(string url)
{
if (Regex.IsMatch(url, #"http(s)?://([\w-]+\.)+[\w-]+(/[\w- ./?%&=]*)?"))
{
ViewData["AnchorText"] = url;
return View(new Website(url, "Url"));
}
return RedirectToAction("Index");
}
The validation is working fine, but what I want to achieve is if the data is not valid, if the data is not proper url, I want to redirect to the same default page with a message probably here: <%= Html.ValidationMessage("url", "*") %> but I don't know how to do that.
Edit
After I did all the changes recommended below, I am getting an error in the header of the view page. I have Inherits="ViewPageBase<Home>" where Home is the name of the class, Home.cs in the Models folder.
In the home.cs file I have this:
namespace LAX.Models
{
public class UrlModel
{
[Required]
[DisplayName("Please enter URL:")]
[RegularExpression(#"http(s)?://([\w-]+\.)+[\w-]+(/[\w- ./?%&=]*)?")]
public string Url { get; set; }
}
}
in the controller I have:
[HttpPost]
public ActionResult WebsiteLinks(UrlModel model)
{
/*
if (Regex.IsMatch(url, #"http(s)?://([\w-]+\.)+[\w-]+(/[\w- ./?%&=]*)?"))
{
ViewData["AnchorText"] = url;
return View(new Website(url, "Url"));
}
else
{
ModelState.AddModelError("url", "Error URL Format");
}
return RedirectToAction("Index");
*/
if (ModelState.IsValid)
{
ViewData["AnchorText"] = model.Url;
return View(new Website(model.Url, "Url"));
}
return RedirectToAction("Index");
}
and in the view I have:
<% using (Html.BeginForm("WebsiteLinks", "Home", FormMethod.Get))
{%>
<%: Html.ValidationSummary("Please enter valid URL and try again.") %>
<fieldset>
<p>
<%=Html.LabelFor(m => m.Url) %>
<%=Html.TextBoxFor(m => m.Url) %>
<%=Html.ValidationMessageFor(m => m.Url) %>
<input type="submit" value="Crawl" />
</p>
</fieldset>
<% } %>
Here is the error: "The type or namespace name 'Home' could not be found (are you missing a using directive or an assembly reference?)"

Answer 1

public ActionResult WebsiteLinks(string url)
{
if (Regex.IsMatch(url, #"http(s)?://([\w-]+\.)+[\w-]+(/[\w- ./?%&=]*)?"))
{
ViewData["AnchorText"] = url;
return View(new Website(url, "Url"));
}
else
{
ModelState.AddModelError("url", "*");
}
return RedirectToAction("Index");
}
or you can make this sexier with DataAnnotations, Model, and a strongly typed View
Model:
public class UrlModel
{
[Required]
[DisplayName("Please enter URL:")]
[RegularExpression(#"http(s)?://([\w-]+\.)+[\w-]+(/[\w- ./?%&=]*)?")]
public string Url { get; set; }
}
Controller:
public ActionResult WebsiteLinks(UrlModel model)
{
if (ModelState.IsValid)
{
ViewData["AnchorText"] = model.Url;
return View(new Website(model.Url, "Url"));
}
return RedirectToAction("Index");
}
View:
<%# Page Language="C#" Inherits="ViewPageBase<UrlModel>" %>
<% using (Html.BeginForm("WebsiteLinks", "Home", FormMethod.Get)) {%>
<%: Html.ValidationSummary("Please enter valid URL and try again.") %>
<fieldset>
<p>
<%=Html.LabelFor(m => m.Url) %>
<%=Html.TextBoxFor(m => m.Url) %>
<%=Html.ValidationMessageFor(m => m.Url) %>
<input type="submit" value="Crawl" />
</p>
</fieldset>
<% } %>