I have a list and setting the list to the exact item that is in it's dataProvider would not select it programmatically. Here is the code:
if (list.selectedItem != iDocument) {
var length:int = documentsCollection.length;
for (var i:int;i<length;i++) {
jDocument = IDocumentData(documentsCollection.getItemAt(i));
if (jDocument.uid==iDocument.uid) {
list.selectedItem = IDocumentData(documentsCollection.getItemAt(i));
break;
}
}
}
There were two issues.
I had applied a sort to the ArrayCollection and the field was not in the item. I had copied code from another project and the field was "#name" since it was an XMLListCollection. The sort field should have been set to "name".
So when you set the selectedItem property it looks in the collection and if the collection has a sort then it looks in the findItem() call which does a compare function that checks if the item has the field name in the item. If not it throws an error. Since I had the incorrect field name an error was thrown. If an error is thrown then the pursuit to find the selected item is abandoned and selected index is -1.
Code from ListCollectionView.as:
try
{
return sort.findItem(localIndex, values, mode, insertIndex);
}
catch (e:SortError)
{
// usually because the find critieria is not compatible with the sort.
}
return -1;
Code from Sort.as:
var hasFieldName:Boolean;
try
{
hasFieldName = values[fieldName] !== undefined;
}
catch(e:Error)
{
hasFieldName = false;
}
if (hasFieldName)
{
if (!hadPreviousFieldName)
{
message = resourceManager.getString(
"collections", "findCondition", [ fieldName ]);
throw new SortError(message);
}
else
{
fieldsForCompare.push(fieldName);
}
}
The second issue was that the List uses an exact equality operator so it uses "===" instead of "==". This means that you have to make sure you are passing in the exact instance of the item in the list.
Related
Is there a way to query cosmos DB for the existence of a property within a document without knowing where exactly this property is located as it might appear in different locations?
Basically
SELECT *
FROM SomeCollection
WHERE IS_DEFINED("here should be just the prop name w/o any path")
Edit:
I initially missed to state that I was looking for a solution on the query level instead of writing a user defined stored procedure
you can create UDF which will recursively navigate though all object properties and return true if found on any level. In your case udf body can look similar to this
function findRecursive(theObject, searchingProperty){
var result = null;
if(theObject instanceof Array) {
for(var i = 0; i < theObject.length; i++) {
if (findRecursive(theObject[i]){
return true;
}
}
}
else
{
for(var prop in theObject) {
if(prop == searchingProperty) {
return true;
}
if(theObject[prop] instanceof Object || theObject[prop] instanceof Array){
if (findRecursive(theObject[prop])){
return true;
}
}
}
}
return false;
}
UDF should be register same as stored procedures. And can be called from queries.
So your select will look like next
SELECT *
FROM root
WHERE udf.findRecursive(root, "here should be just the prop name w/o any path")
P.S. I didn't test the code, but you should get the basic idea
I am implementing a method using Vertx to check the existence of certain value in the database and use Handler with AsyncResult.
I would like to know which one is the best practice:
Option 1: When nothing found, Handler is with succeededFuture but with result as FALSE:
public void checkExistence (..., String itemToFind, Handler<AsyncResult<Boolean>> resultHandler) {
// ....
doQuery(..., queryHandler -> {
if (queryHandler.succeeded()) {
List<JsonObject> results = queryHandler.result();
boolean foundIt = false;
for (JsonObject json: results) {
if (json.getString("someKey").equals(itemToFind)) {
foundIt = true;
break;
}
}
resultHandler.handle(Future.succeededFuture(foundIt));
} else {
resultHandler.handle(Future.failedFuture(queryHandler.cause().toString()));
}
});
}
Option 2: When nothing found, Handler is with failedFuture:
public void checkExistence (..., String itemToFind, Handler<AsyncResult<Void>> resultHandler) {
// ....
doQuery(..., queryHandler -> {
if (queryHandler.succeeded()) {
List<JsonObject> results = queryHandler.result();
boolean foundIt = false;
for (JsonObject json: results) {
if (json.getString("someKey").equals(itemToFind)) {
foundIt = true;
break;
}
}
// HERE IS THE DIFFERENCE!!!
if (foundIt) {
resultHandler.handle(Future.succeededFuture());
} else {
resultHandler.handle(Future.failedFuture("Item " + itemToFind + " not found!"));
}
} else {
resultHandler.handle(Future.failedFuture(queryHandler.cause().toString()));
}
});
}
UPDATE:
Let's say I have another example, instead of checking the existence, I would like to get all the results. Do I check the Empty results? Do I treat Empty as failure or success?
Option 1: only output them when it's not null or empty, otherwise, fail it
public void getItems(..., String itemType, Handler<AsyncResult<List<Item>>> resultHandler) {
// ....
doQuery(..., queryHandler -> {
if (queryHandler.succeeded()) {
List<Item> items = queryHandler.result();
if (items != null && !items.empty()) {
resultHandler.handle(Future.succeededFuture(items));
} else {
resultHandler.handle(Future.failedFuture("No items found!"));
}
} else {
resultHandler.handle(Future.failedFuture(queryHandler.cause().toString()));
}
});
}
Option 2: output results I got, even though it could be empty or null
public void getItems(..., String itemType, Handler<AsyncResult<List<Item>>> resultHandler) {
// ....
doQuery(..., queryHandler -> {
if (queryHandler.succeeded()) {
List<Item> items = queryHandler.result();
resultHandler.handle(Future.succeededFuture(items));
} else {
resultHandler.handle(Future.failedFuture(queryHandler.cause().toString()));
}
});
}
The 1st one option is better, because you can clearly say, that checkExistence returned True or False and completed successfully or it failed with some exception (database issue, etc.).
But lets say, you've decided to stick with 2nd option. Then, imagine you have another method:
void getEntity(int id, Handler<AsyncResult<Entity>> resultHandler);
If entity with provided id doesn't exists, will you throw exception (using Future.failedFuture) or return null (using Future.succeededFuture)? I think, you should throw exception to make your methods logic similar to each other. But again, is that exceptional situation?
For case with returning list of entities you can just return empty list, if there are no entities. Same goes to single entity: it's better to return Optional<Entity> instead of Entity, because in this way you avoid NullPointerException and don't have nullable variables in the code. What's better: Optional<List<Entity>> or empty List<Entity>, it's open question.
Particularly if you're writing this as reusable code, then definitely go with your first option. This method is simply determining whether an item exists, and so should simply return whether it does or not. How is this particular method to know whether it's an error condition that the item doesn't exist?
Some caller might determine that it is indeed an error; it that's the case, then it will throw an appropriate exception if the Future returns with false. But another caller might simply need to know whether the item exists before proceeding; in that case, you'll find yourself using exception handling to compose your business logic.
After reading this article:
http://blogs.msdn.com/b/tilovell/archive/2009/12/29/the-trouble-with-system-activities-foreach-and-parallelforeach.aspx
I have defined the ForEachFactory as follows:
public class ForEachFactory<T> : IActivityTemplateFactory
{
public Activity Create(DependencyObject target)
{
return new ForEach<T>
{
DisplayName = "ForEachFromFactory",
Body = new ActivityAction<T>
{
Argument = new DelegateInArgument<T>("item")
}
};
}
}
All works well but is it possible to check how that DelegeateInArgument in my case named "item" changes its value ?
So if i have defined an array in the variables section and initialized with
{1, 2, 3} i need a way to check how the "item" takes value 1, 2 and then 3.
To be more accurate, i've added this pic, with a breakpoint on the WriteLine activity inside the foreach. When the execution will stop there, is there a way to find out what the value of item is ?
EDIT 1:
Possible solution in my case:
After struggling a bit more i found one interesting thing:
Adding one of my custom activities in the Body of the ForEach, i am able to get the value of the item like this :
So, my activity derives from : CodeActivity
Inside the protected override String[] Execute(CodeActivityContext context) i am doing this job.To be honest, this solves the thing somehow, but it is doable only in my custom activities. If i would put a WriteLine there for example, i would not be able to retrieve that value.
you can access the DelegeateInArgument of a ForEach activity by inspecting the ModelItem trees parent and checking for DelegeateInArgument's. If you need a specific code example to achieve this I may need a some time to code the example. As it has been a long time since I did this, see my question i asked over on msdn
So basically where your break point is, you can access the variable values as these are defined with n the scope of your activity as 'variables'. However the 'item' variable is actually only accessible from the parent loop activity. So you have to get the model item of the current executing activity and then traverse up the tree to find the parent containing the desired DelegateInArgument.
Can you flesh out exactly what you want to achieve? Is it that when your debugging the workflow in the re-hosted designer you want to display the variable values to the user as they change in the UI?
Edit - added tracking example
So as your wanting to display the variable values during execution of the workflow we need to use tracking to achieve this. In the example your using the author has already implemented some basic tracking. So to achieve the extended variable tracking you want you will need to alter the tracking profile.
Firstly amend the WorkflowDesignerHost.xaml.cs file alter the RunWorkflow method to define the SimulatorTrackingParticipant as below.
SimulatorTrackingParticipant simTracker = new SimulatorTrackingParticipant()
{
TrackingProfile = new TrackingProfile()
{
Name = "CustomTrackingProfile",
Queries =
{
new CustomTrackingQuery()
{
Name = all,
ActivityName = all
},
new WorkflowInstanceQuery()
{
**States = {all },**
},
new ActivityStateQuery()
{
// Subscribe for track records from all activities for all states
ActivityName = all,
States = { all },
**Arguments = {all},**
// Extract workflow variables and arguments as a part of the activity tracking record
// VariableName = "*" allows for extraction of all variables in the scope
// of the activity
Variables =
{
{ all }
}
}
}
}
};
This will now correctly capture all workflow instance states rather than just Started/Completed. You will also capture all Arguments on each activity that records tracking data rather than just the variables. This is important because the 'variable' were interested in is actually (as discussed earlier) a DelegateInArgument.
So once we have changed the tracking profile we also need to change the SimulatorTrackingParticipant.cs to extract the additional data we are now tracking.
If you change the OnTrackingRecordReceived method to include the following sections these will capture variable data and also Argument data during execution.
protected void OnTrackingRecordReceived(TrackingRecord record, TimeSpan timeout)
{
System.Diagnostics.Debug.WriteLine(
String.Format("Tracking Record Received: {0} with timeout: {1} seconds.", record, timeout.TotalSeconds)
);
if (TrackingRecordReceived != null)
{
ActivityStateRecord activityStateRecord = record as ActivityStateRecord;
if (activityStateRecord != null)
{
IDictionary<string, object> variables = activityStateRecord.Variables;
StringBuilder vars = new StringBuilder();
if (variables.Count > 0)
{
vars.AppendLine("\n\tVariables:");
foreach (KeyValuePair<string, object> variable in variables)
{
vars.AppendLine(String.Format(
"\t\tName: {0} Value: {1}", variable.Key, variable.Value));
}
}
}
if (activityStateRecord != null)
{
IDictionary<string, object> arguments = activityStateRecord.Arguments;
StringBuilder args = new StringBuilder();
if (arguments.Count > 0)
{
args.AppendLine("\n\tArgument:");
foreach (KeyValuePair<string, object> argument in arguments)
{
args.AppendLine(String.Format(
"\t\tName: {0} Value: {1}", argument.Key, argument.Value));
}
}
//bubble up the args to the UI for the user to see!
}
if((activityStateRecord != null) && (!activityStateRecord.Activity.TypeName.Contains("System.Activities.Expressions")))
{
if (ActivityIdToWorkflowElementMap.ContainsKey(activityStateRecord.Activity.Id))
{
TrackingRecordReceived(this, new TrackingEventArgs(
record,
timeout,
ActivityIdToWorkflowElementMap[activityStateRecord.Activity.Id]
)
);
}
}
else
{
TrackingRecordReceived(this, new TrackingEventArgs(record, timeout,null));
}
}
}
Hope this helps!
My stored procedure, instead of returning zero rows, returns one with most of the columns NULL. When my .Net code sees such data, I wish to force it to display the EmptyDataTemplate. How?
Thanks Win,
In the LinqDataSource Selecting event handler I check if the data source has a size of one and has a null value for one of the key fields and then I pass in this to the LinqDataSourceSelectEventArgs' Result:
using (var dataContext = new WebDataContext())
{
var report = from row in dataContext.GetReport()
select new Report()
{
AccountCode = row.AccountCode //,
//...
}
}
if (report.Count() == 1 && report.ToList()[0].AccountCode == null)
{
var emptyReport = report.ToList();
report.Clear();
e.Result = emptyReport;
}
else
{
//...
e.Result = matrixReport;
//...
}
I am data binding to many FormView controls using EF entity instances, but I have to resort to this ridiculous kludge in order to achieve what I want without using EntityDataSource controls:
propertyHeaderSection.DataSource = new List<PropertyDetailsModel> { _propertyDetails };
I suspect I will have to derive my own control from FormView and enable it to accept an almost POCO as a data source. Where do I start?
This is my implementation, sort of the same idea as patmortech, but i also found out that the ValidateDataSource method on the BaseDataBoundControl is what throws the exception at run-time if your datasource isn't enumerable.
public class CustomFormView : System.Web.UI.WebControls.FormView
{
public override object DataSource
{
get
{
if (!(base.DataSource is IEnumerable))
return new[] {base.DataSource};
return base.DataSource;
}
set
{
base.DataSource = value;
}
}
// This method complains at run time, if the datasource is not
// IListSource, IDataSource or IEnumerbale
protected override void ValidateDataSource(object dataSource)
{
//base.ValidateDataSource(dataSource);
}
}
EDIT:
Considering the suggestion, i've made some changes to the way i check if the assigned DataSource is enumerable or not. I have also managed to create a sample app (VS 2010 Solution) to demo the changes. The app can be downloaded from http://raghurana.com/blog/wp-content/attachments/FormViewDataProblem.zip
In short this is what i am checking to ensure that the existing datasource can be enumerated already or not:
public static bool CanEnumerate( this object obj )
{
if (obj == null) return false;
Type t = obj.GetType();
return t.IsArray ||
t.Implements(typeof (IEnumerable).FullName) ||
t.Implements(typeof (IListSource).FullName) ||
t.Implements(typeof (IDataSource).FullName);
}
Please feel free to suggest more changes, if this isnt quite the desired functionality. Cheers.
Not sure it's the best idea in the world, but this is how you could derive from FormView to allow single object data source values. It basically does the same check that the ValidateDataSource does internally, and then creates a list wrapper for the item if it's not already a valid type.
public class SingleObjectFormView : System.Web.UI.WebControls.FormView
{
public override object DataSource
{
get
{
return base.DataSource;
}
set
{
//will check if it's an expected list type, and if not,
//will put it into a list
if (! (value == null || value is System.Collections.IEnumerable || value is System.ComponentModel.IListSource || value is System.Web.UI.IDataSource) )
{
value = new List<object> { value };
}
base.DataSource = value;
}
}
}