wpf search in collection - wpf

How do I search into my collection ??
Can't get it working... Don't I just have to do :
Contacts c = new Contacts();
if (c.Contact_name == "Test") {
MessageBox.Show("exists!");
}
Does not work :-)
public ObservableCollection<Contacts> contacts = new ObservableCollection<Contacts>();
class Contacts
{
public string Contact_id { get; set; }
public string Contact_name { get; set; }
}

You're setting c to a new instance of Contacts which does not have the Contact_name property set to anything...
If you're trying to search a collection for a specific contact, the easiest way would probably be to use the following Linq statement, which will return the first object in the collecting matching your condition, or null if no object is found
contacts.FirstOrDefault(p => p.Contact_name == "Test");
There's other Linq extensions that may be better suited for you depending on what you want too, such as .Exists() if you only want to know if an item exists or not
If you're not using Linq, the easiest way would be with a loop
foreach(var c in contacts)
{
if (c.Contact_name == "Test") {
MessageBox.Show("exists!");
}
}

Related

map key value pair with entity properties in entity framework

Below is my code for entity and a function where I need to map entity TblEmployee from a key value pair.
In foreach loop I am getting values based on keys, what should be the best approach to do it?
public class TblEmployee
{
public int EmployeeId { get; set; }
public string Name { get; set; }
}
public int Create()
{
tblEmployee employee = new tblEmployee();
using (var ctx = new theparkeee_testEntities())
{
foreach (string key in HttpContext.Current.Request.Form.AllKeys)
{
string value = HttpContext.Current.Request.Form[key];
//how to map value from key value pair to entity employee.
}
}
}
You can use System.Reflection to get the Properties of an object by their name with Type.GetProperty(string name). After you got the PropertyInfo, you can use SetValue to assign a value to it.
foreach (string key in HttpContext.Current.Request.Form.AllKeys) {
// note that "value" is a reserved word, do not use it as variable name
string val = HttpContext.Current.Request.Form[key];
var propertyInfo = typeof(TblEmployee).GetProperty(key); // can maybe be moved outside of the loop
if (propertyInfo != null) {
propertyInfo.SetValue(employee, val);
}
}
This will work for string properties. If the property is of another type, you have to find the correct type (again, using reflection) and cast the string value before assigning it.
Note that this is not the correct approach to store data in MVC. You should not work with the Request.Form directly, instead your POST action should accept a ViewModel that can be mapped (e.g. using Automapper) to the DB entity. I.e. let the ASP ModelBinder do its work, instead of reinventing the wheel!
[HttpPost]
public ActionResult Submit(MyViewModel postData) {
var employee = Mapper.Map<TblEmployee>(postData);
_ctx.Employees.Add(employee);
_ctx.SaveChanges();
return new HttpStatusCodeResult((int)HttpStatusCode.OK);
}

Azure Search - Query

So I'm using the C# nuget wrapper around Azure Search. My problem is I have a index of products:
public class ProductDocument
{
[System.ComponentModel.DataAnnotations.Key]
public string Key { get; set; }
[IsSearchable]
public string Sku { get; set; }
[IsSearchable]
public string Name { get; set; }
[IsSearchable]
public string FullDescription { get; set; }
[IsSearchable]
public List<CustomerSkuDocument> CustomerSkus { get; set; }
}
public class CustomerSkuDocument
{
[IsSearchable]
public int AccountId { get; set; }
[IsSearchable]
public string Sku { get; set; }
}
Example data would be:
new Product() { Key= 100,Name="Nail 101",Sku = "CCCCCCCC", CustomerSkus = new List<ProductCustomerSku>()
{
new ProductCustomerSku() {AccountId = 222, CustomerSku = "BBBB"},
new ProductCustomerSku() {AccountId = 333, CustomerSku = "EEEEEEE"}
}
So the problem is around CustomerSkuDocument.
When I Search I need to pass the AccountId in as well as the search term, however the AccountId is only used for when searching the ProductCustomerSkus.
Basically an Account can have different customer skus but it's only associated to that account - I don't want a separate index per account.
So my call would be something like /AccountId=222&term=BBBB which would find the match.
However /AccountId=333&term=BBBB would not find a match.
So I'm calling it like:
SearchParameters sp = new SearchParameters();
sp.SearchMode = SearchMode.Any;
sp.QueryType = QueryType.Full;
DocumentSearchResult<ProductDocument> results =
productIndexClient.Documents.Search<ProductDocument>(term, sp);
Where term is the normal search term, tried it with adding the AccountId but it doesn't work.
Azure Search does not support repeating data structures nested under a property of the outer document. We're working on this (see https://feedback.azure.com/forums/263029-azure-search/suggestions/6670910-modelling-complex-types-in-indexes), but we still have some work to do before we can release that.
Given that, the example you're showing is not probably indexing the nested parts. Can you post the search index definition you're using? While we work in direct support for complex types, you can see your options for approach here: https://learn.microsoft.com/en-us/azure/search/search-howto-complex-data-types
From the above you'll arribe at a index structure that will also guide your query options. If all you need is equality, perhaps you can simply include the accountId and the SKU in the same field and use a collection field so you can have multiple instances. For your query you would issue a search query that requires the accountId and has the rest as optional keywords.

Dapper multi-mapping not returning null object when splitOn column is not in child object

I'm using dapper 1.50.2 with MySQL and running into a problem trying to map a left outer join child object to its parent. If I split on a column alias that doesn't actually exist in the child object, Dapper always creates a child object with default properties, even when there is nothing in the left join.
I created a simple example to demonstrate this:
public class ParentRecord
{
public string MemberID { get; set; }
public ChildRecord Child { get; set; }
}
public class ChildRecord
{
//public string Split { get; set; }
public string SomeField { get; set; }
}
using (MySqlConnection connection = new MySqlConnection(connectionString))
{
ParentRecord result = connection.Query<ParentRecord, ChildRecord, ParentRecord>(
#"SELECT 'FakeID' AS MemberID, NULL AS Split, NULL AS SomeField",
(mt, crt) =>
{
mt.Child = crt;
return mt;
},
splitOn: "Split").Single();
}
I would expect this to result a ParentRecord with the Child property set to null, but the Child property is set to a ChildRecord with all default fields.
If I uncomment the Split property in ChildRecord, or if I split on SomeField, this works as I'd expect.
Are there any good workarounds for this?
In the actual query I'm dealing with, there are multiple primary key and foreign key fields with the same names and I'd rather not change the property names in the POCOs to be unique. I'd prefer to be able to use column aliases that are just there to split on. I know this isn't normally how Dapper is set to up to work.
Any help would be appreciated, thanks.
This happen because the object Child initialize for default when you attribute the ctr param. Then the solution that I did implement was:
ParentRecord result = connection.Query<ParentRecord, ChildRecord, ParentRecord>(
#"SELECT 'FakeID' AS MemberID, NULL AS Split, NULL AS SomeField",
(mt, crt) =>
{
if (crt.SomeField != null){ mt.Child = crt; }
return mt;
},
splitOn: "Split").Single();

Is there an equivalent to "NotMapped" for Dapper.Net and the Dapper.Net extensions?

I've started to play with Dapper.Net, and am really loving it so far - however, I have run into one problem.
Say that I have a POCO class like:
public class Person
{
public string FirstName { get; set; }
public string LastName { get; set; }
public string FullName { get { return FirstName + " " + LastName; } }
}
Now, using Dapper.Net and the Dapper.Net extensions, I want to simply load all instances of that data type from the DB by doing this:
string connectionString = CloudConfigurationManager.GetSetting("DBConnection");
using (SqlConnection cn = new SqlConnection(connectionString))
{
cn.Open();
IEnumerable<Types.Person> entities = cn.GetList<Types.Person>();
var forceMe = entities.ToList();
}
This works fine in the Linq setup, but when it hits the line with the .ToList(), which forces the evaluation, it blows up with "invalid column names" on FullName. Thinking that it might respect the Entity Framework DataAnnotations stuff for NotMapped, I tried adding a NotMapped attribute (after adding EF 5 to the project). This didn't work.
So, the question is, how do I tell Dapper.Net that a column isn't to be expected from the DB? Is this a problem with the extensions, trying to map a DB column for everything it sees in the model POCO? Do I need to revert to writing SQL, and explicitly ask for the columns that I want only, or is there a way to get an equivalent to NotMapped on the column?
I think the only way to to ignore certain properties from being mapped is to implement an auto class mapper, where you can specify your custom field mappings. For example:
public class CustomMapper : ClassMapper<Foo>
{
public CustomMapper()
{
Table("FooTable");
Map(f => f.Id).Column("FooId").Key(KeyType.Identity);
Map(f => f.DateOfBirth).Column("BirthDate");
Map(f => f.FirstName).Column("First");
Map(f => f.LastName).Column("Last");
Map(f => f.FullName).Ignore();
Map(f => f.Calculated).ReadOnly();
}
}
public class Foo
{
public int Id { get; set; }
public DateTime DateOfBirth { get; set; }
public string FirstName { get; set; }
public string LastName { get; set; }
public string FullName
{
get { return string.Format("{0} {1}", FirstName, LastName); }
}
}
In the above example, FullName is being ignored.
The auto-mapper also allows you to adjust table names, in case your POCO class names do not match table names.
Also, keep in mind that you must keep your custom maps in the same assembly as your POCO classes. The library uses reflection to find custom maps and it only scans one assembly.
Hope this helps,
Good luck

.Net WCF RIA Services parameterized NameValue method crashing

I added a RIA Domain Service method to return a simple NameValuePair of two properties from a table (and filtered on a key value).
It compiles fine, but blows up every time without giving a useful error.
What am I missing? (probably something really obvious)
e.g.:
public IQueryable<NameValuePair> GetNameValues(int keyId)
{
// NOTE: I can breakpoint here and the correct keyId is passed
// it blows up on returning from this method
return from p in this.ObjectContext.NameTable
where p.KeyId == keyId
select new NameValuePair(p.NameValue, p.NameType);
}
Simple NameValuePair Code:
public class NameValuePair
{
[Key]
public string Name { get; set; }
public string Value { get; set; }
public NameValuePair()
{
}
public NameValuePair( string name, string value)
{
this.Name = name;
this.Value = value;
}
}
Update:
I tried returning a query on a static list of NameValuePair objects and that works fine (but is not useful).
I tried this here and got the error: base {System.SystemException} = {"Only parameterless constructors and initializers are supported in LINQ to Entities."}
So you have to change it to create the object first, then pass the property values:
public IQueryable<NameValuePair> GetNameValues(int keyId)
{
return from p in this.ObjectContext.NameTable
where p.KeyId == keyId
select new NameValuePair {Name = p.NameValue, Value = p.NameType};
}

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