For reference I'm using the Serenity application template.
I have the following code
var query = new SqlQuery();
query.From("TenantData")
.Select("ItemData")
.Select("ItemType")
.Where(new Criteria("TenantID") == userDefinition.TenantId);
using (var connection = sqlConnections.NewByKey("Default"))
{
var data = connection.Query(query);
}
The data returned looks like {{DapperRow, ItemData = '2342342wef', ItemType = 'test'}}
What I'm struggling with is how to convert this into a dictionary (ItemData being the key, ItemType being the value).
I've tried a select but it doesn't seem to be supported so I'm at a bit of a loss.
The following should work.
var data = connection.Query(query);
var d = data.ToDictionary(row => (string)row.itemdata, row => (string)row.itemtype);
Make sure you add the using System.Linq; at the top. ToDictionary() is an extension method.
Related
I am currently updating a BackEnd project to .NET Core and having performance issues with my Linq queries.
Main Queries:
var queryTexts = from text in _repositoryContext.Text
where text.KeyName.StartsWith("ApplicationSettings.")
where text.Sprache.Equals("*")
select text;
var queryDescriptions = from text in queryTexts
where text.KeyName.EndsWith("$Descr")
select text;
var queryNames = from text in queryTexts
where !(text.KeyName.EndsWith("$Descr"))
select text;
var queryDefaults = from defaults in _repositoryContext.ApplicationSettingsDefaults
where defaults.Value != "*"
select defaults;
After getting these IQueryables I run a foreach loop in another context to build my DTO model:
foreach (ApplicationSettings appl in _repositoryContext.ApplicationSettings)
{
var applDefaults = queryDefaults.Where(c => c.KeyName.Equals(appl.KeyName)).ToArray();
description = queryDescriptions.Where(d => d.KeyName.Equals("ApplicationSettings." + appl.KeyName + ".$Descr"))
.FirstOrDefault()?
.Text1 ?? "";
var name = queryNames.Where(n => n.KeyName.Equals("ApplicationSettings." + appl.KeyName)).FirstOrDefault()?.Text1 ?? "";
// Do some stuff with data and return DTO Model
}
In my old Project, this part had an execution from about 0,45 sec, by now I have about 5-6 sec..
I thought about using compiled queries but I recognized these don't support returning IEnumerable yet. Also I tried to avoid Contains() method. But it didn't improve performance anyway.
Could you take short look on my queries and maybe refactor or give some hints how to make one of the queries faster?
It is to note that _repositoryContext.Text has compared to other contexts the most entries (about 50 000), because of translations.
queryNames, queryDefaults, and queryDescriptions are all queries not collections. And you are running them in a loop. Try loading them outside of the loop.
eg: load queryNames to a dictionary:
var queryNames = from text in queryTexts
where !(text.KeyName.EndsWith("$Descr"))
select text;
var queryNamesByName = queryName.ToDictionary(n => n.KeyName);
one can write queries like below
var Profile="developer";
var LstUserName = alreadyUsed.Where(x => x.Profile==Profile).ToList();
you can also use "foreach" like below
lstUserNames.ForEach(x=>
{
//do your stuff
});
I am trying to convert a Linq result in to a datatable
I have a linq that is created from a dataset of many tables. It returns results, but I need to get the results in to a new datatable.
Examples I have seen say I sould be able to use .CopyToDataTable But for some reason this doesn't work?
I have noticed that I can to .ToArray perhaps I can then turn the array in to a datatable? Seems line an unnecessary step?
Here is my query: (it works)
Dim R2 = From Inq In DS.Tables!CNLocalInquiry.AsEnumerable()
Join Cust In DS.Tables!CustomerID.AsEnumerable() On Inq.Field(Of Integer)("CNLocalInquiry_Id") Equals Cust.Field(Of Integer)("CNLocalInquiry_Id")
Select New With {.date = Inq.Field(Of String)("date"),
.CName = Cust.Field(Of String)("CustomerNumber"),
.Name = Cust.Field(Of String)("name")}
Dim MemberInq as new datatable
MemberInq = R2.CopyToDataTable() <-- this doesn't work
This is what my query returns:
(this is the easy to code way... this will not be performant for large datasets)
public static class ToolsEx
{
public static DataTable ToDataTable<T>(this IEnumerable<T> items)
{
var t = typeof(T);
var dt = new DataTable(t.Name);
var props = t.GetProperties()
.Select(p => new { N = p.Name, Getter = p.GetGetMethod() })
.Where(p => p.Getter != null)
.ToList();
props.ForEach(p => dt.Columns.Add(p.N));
foreach (var item in items)
dt.Rows.Add(props.Select(p => p.Getter.Invoke(item, null)).ToArray());
return dt;
}
}
I've saved this as an extension method and it's always worked perfectly:
https://msdn.microsoft.com/en-us/library/bb669096.aspx
Examples here:
https://msdn.microsoft.com/en-us/library/bb386921.aspx
Hope that does the trick!
I want to convert my class to a Map so I'm using Serialization package. From the example it looks simple:
var address = new Address();
address.street = 'N 34th';
address.city = 'Seattle';
var serialization = new Serialization()
..addRuleFor(Address);
Map output = serialization.write(address);
I expect to see an output like {'street' : 'N 34th', 'city' : 'Seattle'} but instead it just output something I-don't-know-what-that-is
{"roots":[{"__Ref":true,"rule":3,"object":0}],"data":[[],[],[],[["Seattle","N 34th"]]],"rules":"{\"roots\":[{\"__Ref\":true,\"rule\":1,\"object\":0}],\"data\":[[],[[{\"__Ref\":true,\"rule\":4,\"object\":0},{\"__Ref\":true,\"rule\":3,\"object\":0},{\"__Ref\":true,\"rule\":5,\"object\":0},{\"__Ref\":true,\"rule\":6,\"object\":0}]],[[],[],[\"city\",\"street\"]],[[]],[[]],[[]],[[{\"__Ref\":true,\"rule\":2,\"object\":0},{\"__Ref\":true,\"rule\":2,\"object\":1},\"\",{\"__Ref\":true,\"rule\":2,\"object\":2},{\"__Ref\":true,\"rule\":7,\"object\":0}]],[\"Address\"]],\"rules\":null}"}
Serialization is not supposed to create human-readable output. Maybe JSON output is more what you look for:
import dart:convert;
{
var address = new Address();
..address.street = 'N 34th';
..address.city = 'Seattle';
var encoded = JSON.encode(address, mirrorJson);
}
Map mirrorJson(o) {
Map map = new Map();
InstanceMirror im = reflect(o);
ClassMirror cm = im.type;
var decls = cm.declarations.values.where((dm) => dm is VariableMirror);
decls.forEach((dm) {
var key = MirrorSystem.getName(dm.simpleName);
var val = im.getField(dm.simpleName).reflectee;
map[key] = val;
});
return map;
}
The new Address() creates a full prototype object which is what you are seeing. That being said, they could have done something to avoid part of those, but if you want to restore the object just the way it is, that's necessary.
To see the full content of an object you use the for() instruction in this way:
for(obj in idx) alert(obj[idx]);
You'll see that you get loads of data this way. Without the new Address() it would probably not be that bad.
Serialization won't help you here...
You might give a try to JsonObject library, and maybe go through this in depth explanation how to do what you are trying to do using mirrors.
So I want to allow the user to conditionally turn columns on/off in a Cardboard app I built. I have two problems.
I tried using the 'columns' attribute in the config but I can't seem to find a default value for it that would allow ALL columns to display(All check boxes checked) based on the attribute, ie. the default behavior if I don't include 'columns' in the config object at all (tried null, [] but that displays NO columns).
So that gets to my second problem, if there is no default value is there a simple way to only change that value in the config object or do I have to encapsulate the entire variable in 'if-else' statements?
Finally if I have to manually build the string I need to parse the values of an existing custom attribute (a drop list) we have on the portfolio object. I can't seem to get the rally.forEach loop syntax right. Does someone have a simple example?
Thanks
Dax - Autodesk
I found a example in the online SDK from Rally that I could modify to answer the second part (This assumes a custom attribute on Portfolio item called "ADSK Kanban State" and will output values to console) :
var showAttributeValues = function(results) {
for (var property in results) {
for (var i=0 ; i < results[property].length ; i++) {
console.log("Attribute Value : " + results[property][i]);
}
}
};
var queryConfig = [];
queryConfig[0] = {
type: 'Portfolio Item',
key : 'eKanbanState',
attribute: 'ADSK Kanban State'
};
rallyDataSource.findAll(queryConfig, showAttributeValues);
rally.forEach loops over each key in the first argument and will execute the function passed as the second argument each time.
It will work with either objects or arrays.
For an array:
var array = [1];
rally.forEach(array, function(value, i) {
//value = 1
//i = 0
});
For an object:
var obj = {
foo: 'bar'
};
rally.forEach(obj, function(value, key) {
//value = 'bar'
//key = 'foo'
});
I think that the code to dynamically build a config using the "results" collection created by your query above and passed to your sample showAttributeValues callback, is going to look a lot like the example of dynamically building a set of Table columns as shown in:
Rally App SDK: Is there a way to have variable columns for table?
I'm envisioning something like the following:
// Dynamically build column config array for cardboard config
var columnsArray = new Array();
for (var property in results) {
for (var i=0 ; i < results[property].length ; i++) {
columnsArray.push("'" + results[property][i] + "'");
}
}
var cardboardConfig = {
{
attribute: 'eKanbanState',
columns: columnsArray,
// .. rest of config here
}
// .. (re)-construct cardboard...
Sounds like you're building a neat board. You'll have to provide the board with the list of columns to show each time (destroying the old board and creating a new one).
Example config:
{
attribute: 'ScheduleState'
columns: [
'In-Progress',
'Completed'
]
}
I am using the System.Linq.Data library provided here - http://weblogs.asp.net/scottgu/archive/2008/01/07/dynamic-linq-part-1-using-the-linq-dynamic-query-library.aspx
I have the following query which works great and returns an Iqueryable
IQueryable customer =
ctx.Customers.Where(cust => true).Select("new("Name,Address")");
However, how do I access these returned columns? I cannot access them using a lambda expression as follows:
var test = customer.Where(cust=>cust.Name == "Mike").First();
"cust.Name" in the above case cannot be resolved. It does not exist in the list of methods/properties for "cust".
Am i assuming something wrong here. I understand that I am working with an anonymous type. Do I have to create a DTO in this case?
For any IQueryable you have property called ElementType.
You can use it to get the properties as explained below
IQueryable query = from t in db.Cities
selec new
{
Id = t.Id,
CityName = t.Name
};
if(query!=null)
{
Type elementType = query.ElementType;
foreach(PropertyInfo pi in elementType.GetProperties())
{
}
}
Try foreach loop:
var a = _context.SENDERS.Select(x=>new { Address=x.ADDRESS, Company=x.COMPANY });
foreach(var obj in a)
{
Console.WriteLine(obj.Address);
Console.WriteLine(obj.Company);
}