I've got a new instance of an object in a Linq DBML, but don't know of the test if the a date field is empty.I have tried:
If d Is Nothing OrElse IsDBNull(d) OrElse d <= Date.MinValue Then
TextValue = "nada"
Else
TextValue = FormatDateTime(d)
End If
But the result is "12:00:00 am"
edit: Changed variable name the d
edit: note that the SQL field is nullable
I'm trying to get datetime value but here is issue with nullable datetype.
Public Function GetDate(ByVal kodg As Integer) As DateTime
Dim g = From dt In db.xDates _
Join f In db.xGrafiks On dt.КодД Equals f.DateKod _
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Please excuse my stupidity, I tend to find the traversing XML overly complicated.
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Once it gets to staffBio I get an error saying "Object reference not set to an instance of an object." obviously because that node does not exist. My question is how can I assign the value to a variable even when it is empty without having to do a conditional check before each assignment?
How do I get Linq to ignore any parameters that are empty? So Lastname, Firstname, etc? If I have data in all parameters it works fine...
refinedresult = From x In theresult _
Where x.<thelastname>.Value.TestPhoneElement(LastName) And _
x.<thefirstname>.Value.TestPhoneElement(FirstName) And _
x.<id>.Value.TestPhoneElement(Id) And _
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why is this xml
<?xml version="1.0" encoding="utf-8"?>
<items>
<item id="77" cityID="EE12345" cityDatum="15.2.2010. 11:28:35" />
</items>
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If you, as some can't replicate these results, here's a screenshot:
I am finding this weird issue. When I do this > activities.Where(Function(a) (Not a.IsDeleted And a.ParentId = 100) It returns an in-memory query & when I try opening it up, it throws a object not set exception. This only happens when there were no items which satisfied the condition. Shouldn't it be returning an empty set? When there are items satisfying the condition, then it returns a list & works all good.
View 1 RepliesI was wondering what is the best way to make sure a date is 'empty' so that, if it hasn't been set by the user, that situation is testable.
I've checked and found one way of approaching the issue:
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Is the second one more of a stop-gap measure? Is the first way the sanctioned way (which hopefully doesn't entail a lot of complication with testing/setting the values of the date)?
The only way I know of is awkward:
'check for empty return
Dim count As Integer = (From s In myEntity.employee Where employeeID = myEmployeeIDVariable).Count
'If there is a record, then process
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I have a query that 'selects' object of a type:
Dim l as IList(Of Foo) = (From dataRow As DataRow In table.Select()
Where CStr(dataRow("Column1")) = "A"
Select New Foo(CStr(dataRow("Column1")), _
CStr(dataRow("Column2")))).ToList()
What's happening is that if i set a break-point to the constructor of Foo and step, the constructor is hit and the parameters are loaded with the arguments. However, l has empty Foo objects (the members in every object are Nothing). What could be happening here?
i have a date control on form (vb.net) and by default its value is current date. i want to make its value to null or empty so that no date is shown and user choose from the drop down date calendar.
View 9 RepliesI am retrieving some data from the db and using an sqldatareader to read the data. I have a date column in the table which i am retrieving in the following mannervb Dim d as DateIf Not reader.IsDBNull(10) Then d = reader.GetDateTime(10) Else d = ???
View 5 RepliesWhat I'm trying to do is to write a generic rss reader that I plug in any URL into without worry if the feed has all the common properties. For instance in my example below I'm looking for pubDate, however if no pubDate exists in the xml I'd like to return the current Date. I cannot seem to get the syntax right though.
Dim xmldoc As New XDocument
xmldoc = XDocument.Load(url)
Dim feeds = From feed In xmldoc.Descendants("item") Select New With { _
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I'm trying to do some validation testing in VB.NET. If Entity.WeekEndDate.ToString = String.Empty Then ErrorList.Add(New cValidationError("id", "Incorrect Week End Date"))
Where WeekEndDate is of type Date. When I originally build the object, how can I insert a value into WeekEndDate that will generate an empty string(ie. "") when converted from a Date to a String?
I have a report parameter which looks like this: 01.01.2009 00:00:00.Its a date (as string), as you might have guessed :). The problem is, this param can be an empty string as well. So I tried those expressions:
=IIf(IsDate(Parameters!DateTo.Value), CDate(Parameters!DateTo.Value), "")
=IIf(Len(Parameters!DateTo.Value) > 0, CDate(Parameters!DateTo.Value), "")
Both dont work and the value for the textfield where I print the expressions result is always #Error. As soon as I remove the CDate stuff, it works, but I have to use it. IS there another way to achieve that? What I want is to display nothing if its not a date or the date (format dd.mm.yyyy) if its a date.
I am trying to deserialize an Xml file content into a specific object. Everything runs fine but when I include empty tag of type date or time in my xml(having xsd that describes my xml structure) the deserialization fails. What can I do to make deserialization working when empty date tags are appear?
View 1 Repliesi want to show only date in my dropdownlist from the database using linq in vb.net...
but everytime the "time" comes too..how to show only date using linq..
Is it possible to add some hours to linq date result ? something like this:
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Need convert from text to date and in linq.
CVDate(Format([Creation_Date],"mm/dd/yyyy")) = DATE ()-1
how could I put this on a linq query?
Dim requests = MyDataSet.Tables("T_REQUEST")
Dim full = (From a In requests _
Where a!PNR_STATUS.ToString = "S" And a!CREATION_DATE = "03/01/2011" _
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I need to have a query which list all the user according to the date value in the database. Problems is this, in the database the date format is 5/5/2009 4:30:12 but I want to compare with 5/5/2009. I think the value of the based date is 5/5/2009 12:00:00 and that's why I couldn't query it.
The query is something like
dim db = new databcontext
dim user = from u in db.datacontext where u.signUpTime = 5/5/2009 select u.
I have a DataSet where I need to filter the collection where one of the date columns is not null.
How do you term this in LINQ?
This is what I have so far but there is a compiler error on the w.CompletedDate field in the Where clause.
Dim completed = From ins In InspectionDataset.Inspection.AsEnumerable _
Where (Function(w) w.CompletedDate IsNot Nothing) _
Order By ins.Field(Of DateTime)("UpdatedDate")
I have also tried it the below way but the compiler will not allow the DBNull comparison.
Dim completed = From ins In Inspection.AsEnumerable _
Where ins.Field(Of DateTime)("CompletedDate") <> DBNull.Value _
Order By ins.Field(Of DateTime)("UpdatedDate")
Im using the folowing function to return a SelectList. I need a custom format on Descr, but replacing Key.ToString() to Key.ToString("DD/MM/YY") render me the error "Method 'System.String ToString(System.String)' has no supported translation to SQL.". How could i use a custom date format on Descr?
Public Function ReturnDates(ByVal Param_Pesq_Cod As Integer) As SelectList
Dim Qry = From E In DB.Execs _
Where E.Pesq_Cod = Param_Pesq_Cod _
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I have a datatable where there are 3 columns
ID | Name | Date
and i have 4 columns
1 | ABC | 20/07/2012
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I have a simple If..Then like so:
If rhcexists.First.SignatureDate > Date.Today.AddMonths(-6) Then
End If
rhcexists is a simple query to the Entity Model:
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also i have a table called Orders with several columns, they contain information about the order and store the ID of the Customer they belong to.Question is: how can i query that table with (preferably) linq (the datacontext is from LinqToSql) to return the following dataI want to search for any entry with the matching CustomerID which took place, group them by Year, Sum the Totals respectively and add them to the listview?I now i could use lamda expressions and aggregate, its just not clear how (option infer on,db is a datacontext object,CustomerID is an int32 variable):
Dim Orders = (From order In db.Orders Where order.CustomerID = CustomerID).GroupBy(Function(p) p.Date.Year).GetEnumerator
I reckon i'd have to create an anonymous type like the following:
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I am trying the following to select a long date, but becase the value is stored in SQL database as DateTime I am unable to return any results unless minutes and seconds match perfectly...I then tried to use 2 calendars and have the same issue with the DateTime format..
CODE:
I have two tables, a LP_task table and an lp_Update table. I want a complete list of tasks and only updates that were posted during a specific date range. LINQ doesn't seem to support any other join criteria but 'equals'or each task. I want all tasks (left table) even if they don't have an update. (Left Outer Join)
Dim TasksData = (From t In db.LP_Tasks _
Group Join up In db.LP_Updates On t.ID Equals up.TaskID Into upds = Group _
From u In upds.DefaultIfEmpty _
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I have a DataGridView that has some columns with dates. It binds to an in-memory Datatable which gets loaded from an string array of data passed back from the backend Some of the rows returned have nulls for the date columns. Solution 1: If I define the Date column in the DataTable as "string" I can easily convert those nulls to empty strings and display it in the grid as empty strings (desired results). However, if the user clicks on the date column header to sort by date, it doesn't order the rows as you want. You get a purely string sort order. Not acceptable
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Title pretty much says it all. How do I format the date of a dateandtimepicker to insert it into the SQL date datatype?
View 20 RepliesThis must've have been asked before but I couldn't locate it. In a mixed code project (VB and C#) we were debugging some old Visual Basic code where a statement as follows could be found:
If Request.Params("xxx") <> "" Then
'do something
I considered this a bug as Request.Params could be null, in which case the statement would've become false which wasn't the idea. So I thought. I just found out, -- probably for the tenth time and I will keep forgetting -- that the following two statements are not equal, while Nothing in VB should be equal to null in C# (thought I):
if(String.Empty == null) // always false
If String.Empty = Nothing Then ' always true
Should I dismiss this as a typical Microsoft backward compatibility effort, or should I consider this a huge error in the VB.NET compiler? Does anybody know the Microsoftean opinion on this oddity?
I have a array of strings and I am looping through them, but the string might be empty so I am trying this:
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