can I somehow mark property in my "input object" that goes to action as being mandatory and that it needs to be valid. I.e. if I have:
public class MyInput
{
//[SuperNeeded]
public int FooBar { get; set; }
public string Other { get; set; }
}
I'd like to ASP.NET stack throw an exception when request without FooBar or when FooBar isn't number comes. These are valid:
FooBar=1&Other=abc
FooBar=3
But these are not (don't want FooBar to be 0):
FooBar=abc&Other=abc //FooBar is not number
Other=abc //FooBar is missing
Any ideas how to easily do it?
Have you tried using RequiredAttribute?
In which case, you'd want:
[Required]
public int? FooBar { get; set; }
That way you won't simply get 0, you'll get null if it was missing, and 0 if a 0 was passed in.
Related
I am getting all customers and including their linked operator.
The only catch is a customer can exist without an operator.
The problem I am having is when i try include the operator any customer that doesn't have a linked operator is not retrieved is there a way to still retrieve all my customers and if thy do not have an operator just have the operator object within the customer be null?
-get all customers method
public List<Customer> GetAllWithRelations()
{
return Context.Set<Customer>()
.Include(cp => cp.Operator).ToList();
}
-Cusomer object
public class Customer
{
public int Id { get; set; }
public string Name { get; set; }
public int? OperatorId { get; set; }
[ForeignKey("OperatorId")]
public virtual Operator Operator { get; set; }
}
-Operator Object
public class Operator
{
public int Id { get; set; }
public string Name { get; set; }
}
Although you did not specify a tag for this, by using the .Include I'm guessing it's a EntityFramework Core linq which is breaking.
I've came across the same case on EF whenever the relationship is not set to allow nulls. So, for instance, your mapping might be explicitly setting it to be required or somehow you're not setting it and EF defaults are stablishing a required map between Customer and Operator.
Just set it to optional wherever you're building your model mappings and you'll get the desired behavior.
See: https://learn.microsoft.com/en-us/ef/core/modeling/required-optional
I am facing issue while passing null parameter values to properties of my model in HttpGet verb.
I am using .Net Core 2.1 for my web API project. Below is my action method in controller:
[HttpGet("get")]
public ActionResult GetData([FromQuery]MyTestModel model)
{
var result = new MyTestModel();
return new JsonResult(result);
}
And my MyTestModel.cs is like :
[Serializable]
public class MyTestModel
{
public MyTestModel()
{
PageNo = 1;
PageSize = 10;
}
public int ClientId { get; set; }
public int? CandidateId { get; set; }
public DateTime? FromDate { get; set; }
public DateTime? ToDate { get; set; }
public int PageNo { get; set; }
public int PageSize { get; set; }
}
When I call the API like :
api/controller/get?clientId=7583&candidateId=null&fromDate=null&toDate=null
I am getting 400 response. Below is the response message:
{"toDate":["The value 'null' is not valid for ToDate."],
"fromDate":["The value 'null' is not valid for FromDate."],
"candidateId":["The value 'null' is not valid for CandidateId."]
}
When I don't send nullable properties at all(candidateId, fromDate,toDate), this hits my action and uses default values as null.
What's the problem if I am trying to explicitly setting null values?
Do I need to set some configuration in my Startup.cs to handle null values for nullable properties?
Any help will be appreciated .
Thanks in advance.
Everything sent in the query string is just a string. So, when you do something like toDate=null, you're actually saying "set toDate to "null"", i.e. the string "null". The modelbinder attempts to convert all the strings to the actual types you're binding to, but there's no conversion available that can turn "null" into a null DateTime.
To set the value to null, you need to either pass no value toDate= or just omit the key entirely from the query string.
I'm studying ASP.NET Web API, but somewhere in the explanation about complex types that comes from the request body the author confuses me:
PROFESSIONAL ASP.NET MVC 4: Chapter 11 - ASP.NET Web API
"[..] complex types (everything else) are taken from the body. There is
an additional restriction as well: Only a single value can come from
the body, and that value must represent the entirety of the body.
[...]"
Brad Wilson
What does his mean with this "single value can come from the body"? The API formatters can parse only a single type of object from the body? Could you illustrate this by example?
Only a single value can come from the body
Assume you have a request body like this.
{"Id":12345, "FirstName":"John", "LastName":"West"}
You want this JSON to be bound to a parameter of type like this.
public class Employee
{
public int Id { get; set; }
public string FirstName { get; set; }
public string LastName { get; set; }
}
The action method can be like void Post(Employee emp). And it cannot be like this - void Post(Employee john, Employee duplicateJohn). Only a single value can come from the body.
and that value must represent the entirety of the body
Assume you have the same request body like this.
{"Id":12345, "FirstName":"John", "LastName":"West"}
And you have two DTOs like this.
public class Identifier
{
public int Id { get; set; }
}
public class Name
{
public string FirstName { get; set; }
public string LastName { get; set; }
}
You cannot have an action method like void Post(Identifier id, Name name) and expect the body to be bound partially to both the parameters. Body in its entirety must be bound to only one value. So, having a class like
public class Employee
{
public int Id { get; set; }
public string FirstName { get; set; }
public string LastName { get; set; }
}
and binding the request body in its entirety to one value like void Post(Employee emp) is only allowed.
This basically means that you cannot have multipart body that describes more than one complex type. Say if you have a User type, the entire body must describe that User type and not User + ShoppingChart types.
Valid body for User type:
{
"id" : "1",
"username" : "someuser"
}
Invalid body for User type:
{
"user" : {
"id" : "1",
"username" : "someuser"
},
"shoppingCart" : {
"cartId" : "1",
"items" : "5"
}
}
Of course, you can create a new complex type like UserAndShoppingCart (which uses user and shopping cart classes as properties) and now the invalid body will be valid and deserializable for this new type.
These are my classes:
public class Post : IPost
{
public int Id { get; set; }
public virtual int[] DuplicateOf { get; set; }
public virtual ICommentInfo[] Comments { get; set; }
}
public class CommentInfo : ICommentInfo
{
public virtual string Author { get; set; }
public virtual int Id { get; set; }
public virtual string Text { get; set; }
public virtual int PostId{ get; set; }
[ForeignKey("PostId")]
public virtual Post Post { get; set; }
}
With this CommentConfiguration added to OnModelCreate():
HasRequired(c => c.Post)
.WithMany(b=>(ICollection<CommentInfo>) b.Comments)
.HasForeignKey(b=>b.PostId)
.WillCascadeOnDelete(true);
I really cannot understand why the property Comments is always null, and why EF doesn't initialize it since it's virtual.
I tried disabling lazy loading too, but when i try loading the navigation property with context.Post.Include("Comments") an error tells me that "There is not a navigation property called Comments".
So I tried using Entity Framework Power Tools Beta 3 to see the Entity Data Model, and I discovered that there is not a navigation end for table "Post" even if there is the relationship between the two tables and there's the Comment table end too.
I sincerly don't know which way to turn, could be a problem of Array?? Should I use an Icollection property??
Though I cannot change the type of that property because Post is implementing an Interface.
Every sample I look at is clear and easy to make work. Please help me.. Thank you in advance.
EDIT:
This is what I changed after looking at the link I posted yesterday.
public class Post : IPost
{
public int Id { get; set; }
public virtual int[] DuplicateOf { get; set; }
public virtual ICollection<CommentInfo> Comments { get; set; }
ICommentInfo[] IPost.Comments {
get { return Comments ; }
set { Comments = (CommentInfo[])value; } }
}
The exception is: System.ObjectDisposedException :The ObjectContext instance has been disposed and can no longer be used for operations that require a connection and raises when the application tries to get the Comments.
If I remove the virtual key the exception disappear but the property remain always null and the values don't persist in any way.
EDITv2
I've solved my problem adding a new property and map my old property to it.
public class Post : IPost
{
public int Id { get; set; }
public virtual int[] DuplicateOf { get; set; }
public ICommentInfo[] Comments
{
get { return ListComments.ToArray(); }
}
public List<CommentInfo> ListComments {get;set;}
}
In my PostConfiguration OnModelCreate() I used the ListComments property as a navigation property like this:
HasMany(b => b.ListComments)
.WithRequired(c=>c.Post)
.HasForeignKey(c=>c.PostId)
.WillCascadeOnDelete(true);
Now it perfectly works, it was simpler than I expected and when I try to receive the Comments Collection, if I include the "ListComments" property, I get the array of Post.
Thank you for your help!
I can't access the link in your comment, but I assume you changed
public virtual ICommentInfo[] Comments { get; set; }
into the common way to define navigation properties:
public virtual ICollection<CommentInfo> Comments { get; set; }
because entity framework does not support interfaces in its conceptual model.
The exception about the disposed context means that you access this property after fetching Post objects from the database and disposing the context. This triggers lazy loading while the connection to the database is lost. The solution is to use Include:
var posts = context.Posts.Include(p => p.Comments).Where(...)
Now posts and comments are fetched in one go.
I'm after a little help with the techniques to use for Databinding. It's been quite a while since I used any proper data binding and want to try and do something with the DataGridView. I'm trying to configure as much as possible so that I can simply designed the DatagridView through the form editor, and then use a custom class that exposes all my information.
The sort of information I've got is as follows:
public class Result
{
public String Name { get; set; }
public Boolean PK { get; set; }
public MyEnum EnumValue { get; set; }
public IList<ResultInfos> { get; set; }
}
public class ResultInfos { get; set; }
{
public class Name { get; set; }
public Int Value { get; set; }
public override String ToString() { return Name + " : " Value.ToString(); }
}
I can bind to the simple information without any problem. I want to bind to the EnumValue with a DataGridViewComboBoxColumn, but when I set the DataPropertyName I get exceptions saying the enum values aren't valid.
Then comes the ResultInfo collection. Currently I can't figure out how to bind to this and display my items, again really I want this to be a combobox, where the 1st Item is selected. Anyone any suggestions on what I'm doing wrong?
Thanks
Before you bind your data to the grid, first set the DataGridViewComboBoxColumn.DataSource like this...
combo.DataSource = Enum.GetValues(typeof(YourEnum));
I generally do this in the constructor after InitializeComponent(). Once this is set up you will not get an exception from the combo column when you bind your data. You can set DataGridViewComboBoxColumn.DataPropertyName at design time as normal.
The reason you get an exception when binding without this step is that the cell tries to select the value from the list that matches the value on the item. Since there are no values in the list... it throws an exception.