When Building A Datagrid Helper How To Access The New Data Annotation Attributes Using Reflection
Feb 3, 2010
So I've eagerly added the System.ComponentModel.DataAnnotations namespace to my model.
I've added things such as:
[Required] [DisplayName("First Name")]
public string first_name {get;set;}
I really like these attributes because they save me from having to write custom T4 and/or modify views heavily. This way, I can regenerate a view confident that it will add the display names I want, etc.
The problem comes in when I started building a DataGrid helper inspired by the one in ASP.NET MVC2 unleashed. In this helper, Stephen uses reflection to get at the column headings.
var value=typeOf(T).GetProperty(columnName).GetValue(item,null) ?? String.Empty;
Well, the trouble is I don't want to retrieve the property name. I want to retrieve the value for the DisplayName attribute.
My first attempt at this was to look inside the Attributes property of the PropertyInfo class. Unfortunately, none of the data annotations show up as an attribute.
Is there a way to retrieve the data annotations using reflection?
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[MetadataType(typeof(CustomerMetadata))]
public partial class Customer
{
public class CustomerMetadata
{
[ScaffoldColumn(false)]
public object CustomerId { get; set; }
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}
}
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public class ExtController : Controller
{
protected static Dictionary<Type,List<string>> ControllerRolesDictionary;
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{
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{
// Code to build a menu
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{
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}
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{
// Use this.GetType() to determine if this Controller is already in the Dictionary
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{
// If not, use Reflection to add List of Roles to Dictionary
// associating with Controller
}
}
}
Is this doable? If so, how do I perform Reflection in the ExtController constructor to discover the [Authorize] attribute and related Roles (if any) ALSO! Feel free to go out-of-scope on this question and suggest an alternate way of solving this "Dynamic Site.Master Menu based on Roles" problem. I'm the first to admit that this may not be the best approach.
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[Code]....
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[Code]....
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I am a MVC newbie & am lost in various ways validation can be implemented in my application.
I created a custom model-level data annotation validator attribute, but am unable to display its error message in the view. Basically, I have let's say 5 properties in the Entity class Job (model-level custom attribute called UniqueKeywords defined on it):
1) LoginID: value comes in the URL
2) Title: Required property level attribute defined on it
3) CatID1, CatID2, CatID3 - 3 categoryIDs - these are dropdowns in the view with same list of keywords in all 3.
I want to mandate that the values picked by the user in all 3 category dropdowns should be different.
With reference to the code pasted below, here is the explanation of what happens:
When I submit the form without specifying a title or picking anything from any of the 3 category dropdowns, the validation occurs for the property level Required attribute as well as model level uniquekeywords attribute, but the error is displayed only next to the required field "Title". I can confirm that the custom validation also works by filling in some text in the Title field & then re-posting the form...this re-displays the view, but the error message "Category cannot be duplicated" is not displayed.
Only relevant code sections are pasted below:
My Entity class code:
[Code]....
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