I have the following helper function that uses reflection to look at the supplied model, check if any fields are non-null, and overwrite those with new values in MongoDB.
It works fine until I try updating a List<string> field. Instead of saving the list as an array to MongoDB, it saves a string value of "(Collection)" in MongoDB. What am I missing to make this work?
I don't want to hardcode that any List should default to List<string> either. It's possible I could have lists of ints.
public override MyObj Update(MyObj model)
{
var builder = Builders<MyObj>.Update;
var builder_def = builder.Set(x => x.Id, model.Id);
foreach (PropertyInfo prop in model.GetType().GetProperties())
{
var value = model.GetType().GetProperty(prop.Name).GetValue(model, null);
if (value != null)
{
builder_def = builder_def.Set(prop.Name, value); // Not setting lists correctly
}
}
var filter = Builders<MyObj>.Filter;
var filter_def = filter.Eq(x => x.Id, model.Id);
Connection.Update(filter_def, builder_def);
return model;
}
Edit
I think my problem is related to this open bug https://jira.mongodb.org/browse/CSHARP-1984. Given that, is there any way for me to make this work in that context?
Related
I have a method that takes a List<Dictionary<string,object>> as a parameter. The plan is to use that parameter, but only update the values held in a particular class. Here is the (partially written) method
public async Task<Errors> UpdatePageForProject(Guid projectId, List<Dictionary<string, object>> data)
{
if (!IsValidUserIdForProject(projectId))
return new Errors { ErrorMessage = "Project does not exist", Success = false };
if (data.Count == 0)
return new Errors { ErrorMessage = "No data passed to change", Success = false };
var page = await _context.FlowPages.FirstOrDefaultAsync(t => t.ProjectId == projectId);
foreach (var d in data)
{
}
return new Errors { Success = true };
}
My original plan is to take each dictionary, check if the key and the property in page match and then alter the value (so I can pass in 1 dictionary or 8 dictionaries in the list and then alter page to save back to my entity database).
I'd rather not use reflection due to the speed hit (though C#9 is really fast, I'd still rather not use it), but I'm not sure how else this can be done. I did consider using AutoMapper to do this, but for now would rather not (it's a PoC, so it is possibly overkill)
If you want to do this without Reflection (which I agree is a good idea, not just for performance reasons) then you could use a "map" or lookup table with actions for each property.
var map = new Dictionary<string,Action<Page,object>>()
{
{ "Title", (p,o) => p.Title = (string)o },
{ "Header", (p,o) => p.Field1 = (string)o },
{ "DOB", (p,o) => p.DateOfBirth = (DateTime)o }
};
You can then iterate over your list of dictionaries and use the map to execute actions that update the page.
foreach (var dictionary in data)
{
foreach (entry in dictionary)
{
var action = map[entry.Key];
action(page, entry.Value);
}
}
How i can combine type C# filled model and mongo language for create update request?
i try this but get types error:
var update = new ObjectUpdateDefinition<User>(user) & Builders<User>.Update.Inc(f => f.FindCount, 1);
FullCode:
var user = new Model
{
Email = email,
Language = language,
Password = password,
// +17 fields
};
// how i can convert all fields to set? and join with query Inc (like AllFieldToSet)?
var update = user.AllFieldToSet() & Builders<User>.Update.Inc(f => f.FindCount, 1);
Models.FindOneAndUpdate<Model>(
f => f.Email == email,
update,
new FindOneAndUpdateOptions<Model> {IsUpsert = true});
Firstly I would begin to ask why do you update so many fields at once, this can have a significant effect on performance and scalability, especially when your collection has indexes, replication and/or sharding involved. Whenever you have to update an indexed field it needs to update the index as well.
There are multiple solutions:
ReplaceOne:
Inc only increments the value, this can be done manually in the model: FindCount++
Manually build the update operator: Just manually build using the builder they provided
Write your own extension using reflection Personally I like type safety but you can use this extension that I wrote (you will just have to extend it and build in null checks, etc.)
public static class UpdateBuilderExtensions
{
public static UpdateDefinition<TDocument> SetAll<TDocument, TModel>(this UpdateDefinition<TDocument> updateBuilder, TModel value, params string[] excludeProperties)
{
foreach (var property in value.GetType().GetProperties(BindingFlags.Public | BindingFlags.Instance).Where(x => excludeProperties?.Contains(x.Name) == false))
updateBuilder = Builders<TDocument>.Update.Combine(updateBuilder.Set(property.Name, property.GetValue(value)));
return updateBuilder;
}
}
Usage of it:
You have to exclude properties that have been set already and you have to exclude the BsondId field (if you do not set it manually)
var update = Builders<User>.Update.Inc(x => x.FindCount, 1).SetAll(model, nameof(model.Id), nameof(model.FindCount));
Models.UpdateOne(x => x.Email== "some-email", update, new UpdateOptions
{
IsUpsert = true
});
I want to get the date of creation of a video file, commonly known as Media Created property (not to be confused with the File Creation Date)
I'm trying with this code:
var clip = await MediaClip.CreateFromFileAsync(x);
var encodingProps = clip.GetVideoEncodingProperties();
var props = encodingProps.Properties.ToList();
Inside the props reference I'm getting a list of Guids and values, but I'm lost there.
You can use Extended properties to get the specific property you need:
var dateEncodedPropertyName = "System.Media.DateEncoded";
var propertyNames = new List<string>()
{
dateEncodedPropertyName
};
// Get extended properties
IDictionary<string, object> extraProperties =
await file.Properties.RetrievePropertiesAsync(propertyNames);
// Get the property value
var propValue = extraProperties[dateEncodedPropertyName];
if (propValue != null)
{
Debug.WriteLine(propValue);
}
Note I am using the System.Media.DateEncoded property in the example. If you need a different property, check out the full list of supported properties with their exact names in documentation.
I'm new to using Dynamic Objects in C#. I am reading a CSV file very similarly to the code found here: http://my.safaribooksonline.com/book/programming/csharp/9780321637208/csharp-4dot0-features/ch08lev1sec3
I can reference the data I need with a static name, however I can not find the correct syntax to reference using a dynamic name at run time.
For example I have:
var records = from r in myDynamicClass.Records select r;
foreach(dynamic rec in records)
{
Console.WriteLine(rec.SomeColumn);
}
And this works fine if you know the "SomeColumn" name. I would prefer to have a column name a a string and be able to make the same type refrence at run time.
Since one has to create the class which inherits from DynamicObject, simply add an indexer to the class to achieve one's result via strings.
The following example uses the same properties found in the book example, the properties which holds the individual line data that has the column names. Below is the indexer on that class to achieve the result:
public class myDynamicClassDataLine : System.Dynamic.DynamicObject
{
string[] _lineContent; // Actual line data
List<string> _headers; // Associated headers (properties)
public string this[string indexer]
{
get
{
string result = string.Empty;
int index = _headers.IndexOf(indexer);
if (index >= 0 && index < _lineContent.Length)
result = _lineContent[index];
return result;
}
}
}
Then access the data such as
var csv =
#",,SomeColumn,,,
ab,cd,ef,,,"; // Ef is the "SomeColumn"
var data = new myDynamicClass(csv); // This holds multiple myDynamicClassDataLine items
Console.WriteLine (data.OfType<dynamic>().First()["SomeColumn"]); // "ef" is the output.
You will need to use reflection. To get the names you would use:
List<string> columnNames = new List<string>(records.GetType().GetProperties().Select(i => i.Name));
You can then loop through your results and output the values for each column like so:
foreach(dynamic rec in records)
{
foreach (string prop in columnNames)
Console.Write(rec.GetType().GetProperty (prop).GetValue (rec, null));
}
Try this
string column = "SomeColumn";
var result = rec.GetType().GetProperty (column).GetValue (rec, null);
I think I understand returning records of an anonymous type from But in this I want to create NEW CatalogEntries, and set them from the values selected. (context is a Devart LinqConnect database context, which lets me grab a view).
My solution works, but it seems clumsy. I want to do this in one from statement.
var query = from it in context.Viewbostons
select it;
foreach (GPLContext.Viewboston item in query)
{
CatalogEntry card = new CatalogEntry();
card.idx = item.Idx;
card.product = item.Product;
card.size = (long)item.SizeBytes;
card.date = item.Date.ToString();
card.type = item.Type;
card.classification = item.Classification;
card.distributor = item.Distributor;
card.egplDate = item.EgplDate.ToString();
card.classificationVal = (int)item.ClassificationInt;
card.handling = item.Handling;
card.creator = item.Creator;
card.datum = item.Datum;
card.elevation = (int)item.ElevationFt;
card.description = item.Description;
card.dirLocation = item.DoLocation;
card.bbox = item.Bbox;
card.uniqID = item.UniqId;
values.Add(card);
}
CatalogResults response = new CatalogResults();
I just tried this:
var query2 = from item in context.Viewbostons
select new CatalogResults
{ item.Idx,
item.Product,
(long)item.SizeBytes,
item.Date.ToString(),
item.Type,
item.Classification,
item.Distributor,
item.EgplDate.ToString(),
(int)item.ClassificationInt,
item.Handling,
item.Creator,
item.Datum,
(int)item.ElevationFt,
item.Description,
item.DoLocation,
item.Bbox,
item.UniqId
};
But I get the following error:
Error 79 Cannot initialize type 'CatalogService.CatalogResults' with a
collection initializer because it does not implement
'System.Collections.IEnumerable' C:\Users\ysg4206\Documents\Visual
Studio
2010\Projects\CatalogService\CatalogService\CatalogService.svc.cs 91 25 CatalogService
I should tell you what the definition of the CatalogResults is that I want to return:
[DataContract]
public class CatalogResults
{
CatalogEntry[] _results;
[DataMember]
public CatalogEntry[] results
{
get { return _results; }
set { _results = value; }
}
}
My mind is dull today, apologies to all. You are being helpful. The end result is going to be serialized by WCF to a JSON structure, I need the array wrapped in a object with some information about size, etc.
Since .NET 3.0 you can use object initializer like shown below:
var catalogResults = new CatalogResults
{
results = context.Viewbostons
.Select(it => new CatalogEntry
{
idx = it.Idx,
product = it.Product,
...
})
.ToArray()
};
So if this is only one place where you are using CatalogEntry property setters - make all properties read-only so CatalogEntry will be immutable.
MSDN, Object initializer:
Object initializers let you assign values to any accessible fields or properties of an
object at creation time without having to explicitly invoke a constructor.
The trick here is to create a IQueryable, and then take the FirstOrDefault() value as your response (if you want a single response) or ToArray() (if you want an array). The error you are getting (Error 79 Cannot initialize type 'CatalogService.CatalogResults' with a collection initializer because it does not implement 'System.Collections.IEnumerable') is because you're trying to create an IEnumerable within the CatalogEntry object (by referencing the item variable).
var response = (from item in context.Viewbostons
select new CatalogEntry()
{
idx = item.Idx,
product = item.Product,
size = (long)item.SizeBytes,
...
}).ToArray();
You don't have to create anonymous types in a Linq select. You can specify your real type.
var query = context.Viewbostons.Select( it =>
new CatalogEntry
{
idx = it.idx,
... etc
});
This should work:
var query = from it in context.Viewbostons
select new CatalogEntry()
{
// ...
};