I have 3 nested collections (portfolios, rents and leases) and I get the last one like this:
getRentLeases() {
final portfolio = list.where((portfolio) {
return portfolio['documentID'].contains(currentPortfolioId)
? true
: false;
}).toList();
final rent = portfolio[0]['rents'].where((rent) {
return rent['documentID'].contains(currentRentId) ? true : false;
}).toList();
return rent[0]['leases'];
}
as you see I always have the ID for previous collection saved.
To find a specific lease I could follow similar approach:
var lease = getRentLeases().where((lease) {
return lease['documentID'].contains(newLease['documentID'])
? true
: false;
}).toList();
but how could I update it? Something like this doesn't work:
lease = newLease;
? true : false is not necessary as contains already gives you a boolean value.
If you only expect one item to be returned by the where method, then you should go for singleWhere as it directly gives you the item instead of the list. If none of these or multiple items satisfy the condition, you get an exception.
You should separate getRentLeases into two methods. In this case its even better to have methods returning the index of the relevant item.
Please consider that I only used dynamic because I don't have access to the data types. You should instead type the variables.
Code:
int getIndexOfPortFolio(String portfolioId) {
return list
.indexWhere(portfolio => portfolio['documentID'].contains(portfolioId));
}
int getIndexOfRent(dynamic portfolio, String rentId) {
return portfolio['rents']
.indexWhere(rent => rent['documentID'].toString().contains(rentId));
}
int getIndexOfLease(dynamic rent, String leaseId) {
return rent['leases']
.indexWhere(lease => lease['documentID'].toString().contains(leaseId));
}
And then you can update your object like this:
void updateLease(String portfolioId, String rentId, String oldLeaseId, dynamic newLease) {
int portFolioIndex = getIndexOfPortFolio(portfolioId);
var portFolio = list[portFolioIndex];
int rentIndex = getIndexOfRent(portFolio, rentId);
var rent = portFolio["rents"][rentIndex];
int leaseIndex = getIndexOfLease(rent, oldLeaseId);
rent["leases"][leaseIndex] = newLease;
}
As my application currently sits, each AppUser may (or may not) have 3 phone numbers (UserPhones). One of each type (Mobile, Home, Other).
The following Tag Helper works great (Thanks #itminus).
Calling code from Razor Page:
<user-phones phones="#Model.UserPhones"
asp-for="#Model.UserPhones"
prop-name-to-edit="PhoneNumber"
types-to-edit="new EnumPhoneType[] { EnumPhoneType.Mobile,
EnumPhoneType.Other }" />
Code:
public class UserPhonesTagHelper : TagHelper
{
private readonly IHtmlGenerator _htmlGenerator;
private const string ForAttributeName = "asp-for";
[HtmlAttributeName("expression-filter")]
public Func<string, string> ExpressionFilter { get; set; } = e => e;
public List<UserPhones> Phones { get; set; }
public EnumPhoneType[] TypesToEdit { get; set; }
public string PropNameToEdit { get; set; }
[ViewContext]
public ViewContext ViewContext { set; get; }
[HtmlAttributeName(ForAttributeName)]
public ModelExpression For { get; set; }
public UserPhonesTagHelper(IHtmlGenerator htmlGenerator)
{
_htmlGenerator = htmlGenerator;
}
public override async Task ProcessAsync(TagHelperContext context, TagHelperOutput output)
{
output.TagName = null; //DO NOT WANT AN OUTTER HTML ELEMENT
for (int i = 0; i < Phones.Count(); i++)
{
var props = typeof(UserPhones).GetProperties();
var pType = props.Single(z => z.Name == "Type");
var pTypeVal = pType.GetValue(Phones[i]);
EnumPhoneType eType = (EnumPhoneType) Enum.Parse(typeof(EnumPhoneType), pTypeVal.ToString());
string lVal = null;
switch (eType)
{
case EnumPhoneType.Home:
lVal = "Home Phone";
break;
case EnumPhoneType.Mobile:
lVal = "Mobile Phone";
break;
case EnumPhoneType.Other:
lVal = "Other Phone";
break;
default:
break;
}
//LOOP ALL PROPERTIES
foreach (var pi in props)
{
var v = pi.GetValue(Phones[i]);
var expression = this.ExpressionFilter(For.Name + $"[{i}].{pi.Name}");
var explorer = For.ModelExplorer.GetExplorerForExpression(typeof(IList<UserPhones>), o => v);
//IF REQUESTED TYPE AND PROPERTY SPECIFIED
if (pi.Name.NormalizeString() == PropNameToEdit.NormalizeString() && TypesToEdit.Contains(eType))
{
TagBuilder gridItem = new TagBuilder("div");
gridItem.Attributes.Add("class", "rvt-grid__item");
gridItem.InnerHtml.AppendHtml(BuildLabel(explorer, expression, lVal));
gridItem.InnerHtml.AppendHtml(BuildTextBox(explorer, expression, v.ToString()));
output.Content.AppendHtml(gridItem);
}
else //ADD HIDDEN FIELD SO BOUND PROPERLY
output.Content.AppendHtml(BuildHidden(explorer, expression, v.ToString()));
}
}
}
private TagBuilder BuildTextBox(ModelExplorer explorer, string expression, string v)
{
return _htmlGenerator.GenerateTextBox(ViewContext, explorer, expression, v, null, new { #class = "form-control" });
}
public TagBuilder BuildHidden(ModelExplorer explorer, string expression, string v)
{
return _htmlGenerator.GenerateHidden(ViewContext, explorer, expression, v, false, new { });
}
public TagBuilder BuildLabel(ModelExplorer explorer, string expression, string v)
{
return _htmlGenerator.GenerateLabel(ViewContext, explorer, expression, v, new { });
}
}
My Question:
Lets assume this AppUser only has one related Mobile phone number listed currently. So AppUser.UserPhones (count = 1 of type Mobile). So the code above, as-is, will only render an input for Mobile phone.
Since types-to-edit calls for both Mobile and Other, I want both inputs to be rendered to the screen. And IF the user adds a phone number to the Other input, then it would be saved to the related UserPhones entity on the Razor Pages OnPostAsync method. If the user does NOT provide a number for the "Other" input, then the related UserPhones record of type "Other" should NOT be created.
Can you help?
Thanks again!!!!
TagHelper
As my application currently sits, each AppUser may (or may not) have 3 phone numbers (UserPhones). One of each type (Mobile, Home, Other).
If I understand correctly, an AppUser might have 3 phone numbers and the count of each phone type for every user will be zero or one.
If that's the case, we can simply use PhoneType as an index, in other words, there's no need to use a custom index to iterate through the Phones property, and the ProcessAsync() method could be :
public override async Task ProcessAsync(TagHelperContext context, TagHelperOutput output)
{
output.TagName = null; //DO NOT WANT AN OUTTER HTML ELEMENT
var props = typeof(UserPhones).GetProperties();
// display editable tags for phones
foreach (var pt in this.TypesToEdit) {
var phone = Phones.SingleOrDefault(p=>p.Type == pt);
var index = (int) pt;
foreach (var pi in props)
{
// if phone==null , then the pv should be null too
var pv = phone==null? null: pi.GetValue(phone);
var tag = GenerateFieldForProperty(pi.Name, pv, index, pt);
output.Content.AppendHtml(tag);
}
}
// generate hidden input tags for phones
var phones= Phones.Where(p => !this.TypesToEdit.Contains((p.Type)));
foreach (var p in phones) {
var index = (int)p.Type;
foreach (var pi in props) {
var pv = pi.GetValue(p);
var tag = GenerateFieldForProperty(pi.Name,pv,index,p.Type);
output.Content.AppendHtml(tag);
}
}
}
Here the GenerateFieldForProperty is a simply helper method to generate tag builder for particular property:
private TagBuilder GenerateFieldForProperty(string propName,object propValue,int index, EnumPhoneType eType )
{
// whether current UserPhone is editable (check the PhoneType)
var editable = TypesToEdit.Contains(eType);
var expression = this.ExpressionFilter(For.Name + $"[{index}].{propName}");
var explorer = For.ModelExplorer.GetExplorerForExpression(typeof(IList<UserPhones>), o => propValue);
//IF REQUESTED TYPE AND PROPERTY SPECIFIED
if (pi.Name.NormalizeString() == PropNameToEdit.NormalizeString() && editable)
{
TagBuilder gridItem = new TagBuilder("div");
gridItem.Attributes.Add("class", "rvt-grid__item");
var labelText = this.GetLabelTextByPhoneType(eType);
gridItem.InnerHtml.AppendHtml(BuildLabel(explorer, expression, labelText));
gridItem.InnerHtml.AppendHtml(BuildTextBox(explorer, expression, propValue?.ToString()));
return gridItem;
}
else //ADD HIDDEN FIELD SO BOUND PROPERLY
return BuildHidden(explorer, expression, propValue?.ToString());
}
private string GetLabelTextByPhoneType(EnumPhoneType eType) {
string lVal = null;
switch (eType)
{
case EnumPhoneType.Home:
lVal = "Home Phone";
break;
case EnumPhoneType.Mobile:
lVal = "Mobile Phone";
break;
case EnumPhoneType.Other:
lVal = "Other Phone";
break;
default:
break;
}
return lVal;
}
When posted to server, if someone doesn't input a phone number for the other PhoneType, the actual payload will be something like:
AppUser.UserPhones[0].UserPhoneId=....&AppUser.UserPhones[0].PhoneNumber=911&....
&AppUser.UserPhones[2].UserPhoneId=&AppUser.UserPhones[2].PhoneNumber=&AppUser.UserPhones[2].Type=&AppUser.UserPhones[2].AppUserId=&AppUser.UserPhones[2].AppUser=
&AppUser.UserPhones[1].UserPhoneId=...&AppUser.UserPhones[1].PhoneNumber=119&....
Since we use phone type as the index, we can conclude that the UserPhones[0] will be used as an Mobile phone and the UserPhones[2] will be treated as an Home phone.
page handler or action method
And the model binder on server side will create a empty string for each UserPhone.
To remove those empty inputs and prevent overposting attack, we could use Linq to filter UserPhones so that we can create or update UserPhone records without empty Phones:
var editables = new[] {
EnumPhoneType.Mobile,
EnumPhoneType.Other,
};
AppUser.UserPhones = AppUser.UserPhones
.Where(p => !string.IsNullOrEmpty(p.PhoneNumber)) // remove empty inputs
.Where(p => editables.Contains(p.Type) ) // remove not editable inputs
.ToList();
// now the `UserPhones` will be clean for later use
// ... create or update user phones as you like
Let's say you want to create phones :
public IActionResult OnPostCreate() {
var editables = new[] {
EnumPhoneType.Mobile,
EnumPhoneType.Other,
};
AppUser.UserPhones = AppUser.UserPhones
.Where(p => !string.IsNullOrEmpty(p.PhoneNumber))
.Where(p => editables.Contains(p.Type) )
.Select(p => { // construct relationship for inputs
p.AppUser = AppUser;
p.AppUserId = AppUser.Id;
return p;
})
.ToList();
this._dbContext.Set<UserPhones>().AddRange(AppUser.UserPhones);
this._dbContext.SaveChanges();
return Page();
}
Test Case :
<form method="post">
<div class="row">
<user-phones
phones="#Model.AppUser.UserPhones"
asp-for="#Model.AppUser.UserPhones"
prop-name-to-edit="PhoneNumber"
types-to-edit="new EnumPhoneType[] { EnumPhoneType.Mobile, EnumPhoneType.Other}"
>
</user-phones>
</div>
<button type="submit">submit</button>
</form>
User1 who has Mobile phone and Home phone number:
User2 who wants to create a new Mobile phone number :
The Plan:
So now what I basically want is to take my propertys out of the class, let the user pick some and then pull a List with ONLY those propertys out of MongoDB.
The Code:
here is where the method starts:
private void DoStuffExecute(object obj)
{
Class class= new Class();
ExtractClass(class);
if (propList != null)
{
var result = classService.DoStuff(propList);
}
}
in "ExtractClass()" the Propertys are being pulled out of the Class.
void ExtractClass(object obj)
{
foreach (var item in obj.GetType().GetProperties())
{
propList.Add(item.Name);
}
}
and finally in "classService.DoStuff()" i try to set the "fields".
public List<class> DoStuff(List<string> Props)
{
try
{
var filter = Builders<class>.Filter.Empty;
var fields = Builders<class>.Projection.Include(x => x.ID);
foreach (var item in Props)
{
string str = "x.";
str += item.ToString();
fields = Builders<class>.Projection.Include(x => str);
fields = Builders<class>.Projection.Include(x => item);
}
var result = MongoConnectionHandler.MongoCollection.Find(filter).Project<class>(fields).ToList();
return result;
}
catch (Exception ex)
{
MessageBox.Show(ex.Message);
var result = new List<class>();
return result;
}
}
when i run the programm it gives me an "Unable to determine the serialization information for x=> value"... since im giving it a string.
The Question:
Does anyone have an Idea how to repair the code above or even make the plan work in another way?
thank you.
First of all: you are using such code lines as : var filter = Builders<class>.Filter.Empty; It is not possible, because class is a reserved keyword in c# (https://msdn.microsoft.com/en-us/library/x53a06bb.aspx) I assume, it's your Model, and i will speak about it as about Model class.
Include Filter needs Expression as a parameter, not a string, you should construct is as a expression. That's the second thing. Third, you should combine your includes as a chain, So your part of creating Include Filter from string List should look like:
var filter = Builders<Model>.Filter.Empty;
var fields = Builders<Model>.Projection.Include(x => x.Id);
foreach (var item in Props)
{
var par = Expression.Parameter(typeof(Model));
var prop = Expression.Property(par, item);
var cast = Expression.Convert(prop, typeof(object));
var lambda = Expression.Lambda(cast, par);
fields = fields.Include((Expression<Func<Model, object>>)lambda);
}
I have all expresiions separate for better understanding: first you create Parameter (x=>), than you add property (x=>x.Property1), than you should cast it to object, and after all create Lambda Expression from it.
And now the last part: You don't need all of it, Include function could get jsut a string as a parameter. So you could instead of all expression call write this:
fields = fields.Include(item);
I am implementing a search where I would like to partially match an entity's primary key. For example, if I would search for "123" it would return entities which have primary keys like:
12345
67123
91234
If this were a string, I'd attack it like this:
public PartialViewResult QuickSearch(string searchTerm)
{
var results = db.MyEntities.Where(x => x.myProperty.Contains(searchTerm));
return PartialView("QuickSearch_Results", results);
}
However I'm at a loss on the best way to do this for an int. I'm looking for something like this:
public PartialViewResult QuickSearch(int id)
{
var results = db.MyEntities.Where(x => x.myPropertyId.Contains(int));
return PartialView("QuickSearch_Results", results);
}
But obviously contains is not the right way to go. What would be a correct way of implementing this?
Totally wild and untested guess using the StringConvert method:
public PartialViewResult QuickSearch(int id)
{
string sId = id.ToString();
var results =
from x in db.MyEntities
where SqlFunctions.StringConvert((double)x.myPropertyId)
.Contains(sId)
select x;
return PartialView("QuickSearch_Results", results);
}
db.MyEntities.Where(x => x.myPropertyId.ToString().Contains(id.ToString()));
I Use entity Framework 4.
I would like to be able to create a function that return an Expression func that will be use in a lambda expression.
var ViewModel = _db.Suppliers.Select(model => new {
model,SupType = model.SupplierType.SupplierTypeTexts.Where( st => st.LangID == 1)
});
I would like to make this call like that
var ViewModel = _db.Suppliers.Select(model => new {
model,SupType = model.SupplierType.GetText()
});
My Partial class is:
public partial class SupplierType
{
public Expression<Func<SupplierTypeText, bool>> GetText()
{
return p => p.LangID == 1;
}
How can i perform this.
Easy. For example, Let's assume you have a Product table that is mapped to Products EntitySet in your context, now you want to pass a predicate and select a Product:
Expression<Func<Product, bool>> GetPredicate(int id) {
return (p => p.ProductID == id);
}
You can call GetPredicate() with a Product ID to filter based on that:
var query = ctx.Products.Where(GetPredicate(1)).First();
The point really is that you can always pass a Lambda Expression to where an Expression<T> is needed.
EDIT:
You should change your code like this:
var ViewModel = _db.Suppliers.Select(model => new {
model,
SupType = model.SupplierType.SupplierTypeTexts.Where(GetText())
});
public Expression<Func<SupplierTypeText, bool>> GetText() {
return (stt => stt.LangID == 1);
}
If you want to dynamically create compiled Expression at runtime (as opposed to ones hardcoded against a particular data model at compile time) you need to use the static methods on the Expression class.