How do I get the collection of Model State Errors in ASP.NET MVC? - html

Question

How do I get the collection of errors in a view?
I don't want to use the Html Helper Validation Summary or Validation Message. Instead I want to check for errors and if any display them in specific format. Also on the input controls I want to check for a specific property error and add a class to the input.
P.S. I'm using the Spark View Engine but the idea should be the same.
So I figured I could do something like...
<if condition="${ModelState.Errors.Count > 0}">
DisplayErrorSummary()
</if>
....and also...
<input type="text" value="${Model.Name}"
class="?{ModelState.Errors["Name"] != string.empty} error" />
....
Or something like that.
UPDATE
My final solution looked like this:
<input type="text" value="${ViewData.Model.Name}"
class="text error?{!ViewData.ModelState.IsValid &&
ViewData.ModelState["Name"].Errors.Count() > 0}"
id="Name" name="Name" />
This only adds the error css class if this property has an error.

Answer 1

<% ViewData.ModelState.IsValid %>
or
<% ViewData.ModelState.Values.Any(x => x.Errors.Count >= 1) %>
and for a specific property...
<% ViewData.ModelState["Property"].Errors %> // Note this returns a collection

Answer 2

To just get the errors from the ModelState, use this Linq:
var modelStateErrors = this.ModelState.Keys.SelectMany(key => this.ModelState[key].Errors);

Answer 3

Condensed version of #ChrisMcKenzie's answer:
var modelStateErrors = this.ModelState.Values.SelectMany(m => m.Errors);

Answer 4

This will give you one string with all the errors with comma separating
string validationErrors = string.Join(",",
ModelState.Values.Where(E => E.Errors.Count > 0)
.SelectMany(E => E.Errors)
.Select(E => E.ErrorMessage)
.ToArray());

Answer 5

Putting together several answers from above, this is what I ended up using:
var validationErrors = ModelState.Values.Where(E => E.Errors.Count > 0)
.SelectMany(E => E.Errors)
.Select(E => E.ErrorMessage)
.ToList();
validationErrors ends up being a List<string> that contains each error message. From there, it's easy to do what you want with that list.

Answer 6

Thanks Chad! To show all the errors associated with the key, here's what I came up with. For some reason the base Html.ValidationMessage helper only shows the first error associated with the key.
<%= Html.ShowAllErrors(mykey) %>
HtmlHelper:
public static String ShowAllErrors(this HtmlHelper helper, String key) {
StringBuilder sb = new StringBuilder();
if (helper.ViewData.ModelState[key] != null) {
foreach (var e in helper.ViewData.ModelState[key].Errors) {
TagBuilder div = new TagBuilder("div");
div.MergeAttribute("class", "field-validation-error");
div.SetInnerText(e.ErrorMessage);
sb.Append(div.ToString());
}
}
return sb.ToString();
}

Answer 7

Here is the VB.
Dim validationErrors As String = String.Join(",", ModelState.Values.Where(Function(E) E.Errors.Count > 0).SelectMany(Function(E) E.Errors).[Select](Function(E) E.ErrorMessage).ToArray())

Answer 8

If you don't know what property caused the error, you can, using reflection, loop over all properties:
public static String ShowAllErrors<T>(this HtmlHelper helper) {
StringBuilder sb = new StringBuilder();
Type myType = typeof(T);
PropertyInfo[] propInfo = myType.GetProperties();
foreach (PropertyInfo prop in propInfo) {
foreach (var e in helper.ViewData.ModelState[prop.Name].Errors) {
TagBuilder div = new TagBuilder("div");
div.MergeAttribute("class", "field-validation-error");
div.SetInnerText(e.ErrorMessage);
sb.Append(div.ToString());
}
}
return sb.ToString();
}
Where T is the type of your "ViewModel".

Answer 9

Got this from BrockAllen's answer that worked for me, it displays the keys that have errors:
var errors =
from item in ModelState
where item.Value.Errors.Count > 0
select item.Key;
var keys = errors.ToArray();
Source: https://forums.asp.net/t/1805163.aspx?Get+the+Key+value+of+the+Model+error