string.contains(string) match whole word
<p>In my view,</p>

<pre><code>@using(Html.BeginForm("Action", "Controller", FormMethod.Post)){
&lt;div&gt;
    @Html.TextBox("text_1", " ")
    @Html.TextBox("text_2", " ")
    @if(Session["UserRole"].ToString() == "Manager"){
    @Html.TextBox("anotherText_3", " ")
    }
&lt;/div&gt;
&lt;button type="submit"&gt;Submit&lt;/button&gt;
}
</code></pre>

<p>In my controller,</p>

<pre><code>public ActionResult Action(FormCollection form){
    if(!form.AllKeys.Contains("anotherText")){
        ModelState.AddModelError("Error", "AnotherText is missing!");
    }
}
</code></pre>

<p>I have a form and post to my method, in my method i want to check if a textbox with id that containing "anotherText", but i use .Contains() it always give false which is not found in my formcollection...How can i do so that it check if the textbox of id containing "anotherText" is existed?</p>