If I have a datatble column set as int16 but rows can contain null values for this column. How do i write the linq query. I keep getting an error null value exception. Dim query = From n In resultstable.AsEnumerable Where n.value is dbnull.value does n't work.
View 6 RepliesI have a table with the below structure.
ID VALUE
1 3.2
2 NULL
4 NULL
5 NULL
7 NULL
10 1.8
11 NULL
12 3.2
15 4.7
17 NULL
22 NULL
24 NULL
25 NULL
27 NULL
28 7
I would like to get the max count of consecutive null values in the table.
From r In ReceiptLines
Where
r.RECEIPT.RECEIPTDATE >= _reportStartDate
And r.RECEIPT.RECEIPTDATE <= _reportEndDate
[Code].....
I am fetching all departments and their sales, average, count from the ReceiptLine, Receipt, ReceiptDiscount tables. The problem i am facing is, if i remove where discount > 0, I am getting null exception. But if I include that, then I only get sales that has discount. How would I write query that bring all sales less discount (if it has one).
I am working on a program that has many integers (q1, q2, etc.), and each of them can be 0 or 1. This is dependent on which radiobuttons are selected. I need it to check and make sure that all of the integers have a value, but since "Null" is the same as "0",
View 8 RepliesI am using a GridView in asp.net 2.0 and I want to perform inline editing. I am using an object datasource. Because I want to use validation controls on the integer fields in my gridview, I have made them into <TemplateFields> and added a datatype validator and a range validator. This allows me to either have a blank field, or an integer value between 0 and 999.I am trying to display a "-" when the value of the property is not defined. There is no Null for an integer, so I have decided to use -1 as the value to indicate a Null.I am reformatting the to display the "-" if the value is -1. I do that as follows:
<ItemTemplate>
<asp:Label ID="lblPC" runat="server" Text='<%# FormatIntegerToText(Eval("PitchCount"),"-") %>'></asp:Label>
</ItemTemplate>
In the code behind I have defined the function FormatIntegerToText as follows:
Protected Function FormatIntegerToText(ByVal value As Object, ByVal nullvalue As String) As String
' Make sure value is not null... if so, return "-"
If value = Null.NullInteger() Then
Return nullvalue
[code]....
I though I could do the following to reformat the value that is placed in the text box:
<EditItemTemplate>
<asp:textbox ID="txtPC" runat="server" Text='<%# FormatIntegerToText(Bind("PitchCount")) %>' width="25" Columns="2"></asp:textbox>
but when I do this I get a compilation error that Bind is not a recognized function.why is this not allowed, and how can I work around it?
Checked out the video on MS website by Beth Massi and downloaded the project.
One query she uses this statement,[code...]
I'm I missing a reference or something? This is an Access DB, does that make a difference?
I have been looking into dynamic querying of datasets and the use of copytodatatable() for a project. I have seen in alot of forums that the copytodatatable functionality is unusable as it was removed. have an example of a dynamic Linq query being loaded into a datatable.
View 1 RepliesI have this LINQ statement [code]...
Is there any way that I can use if/iif within select ?
How to check whether a column is null i use the following code but I got this error "Input string was not in a correct format."
[Code]....
I have a class and method exposed to a client asp.net app. The class looks like
<DataContract()> _
Public Class Class1
Private v_string As String
Private v_integer As Integer
[code]....
The method is declared as
<OperationContract()> _
Function GetStuff(ByVal bar As Class1) As String
In the client code I create an instance of Class1 and set the values for v_string and v_integer, but using Wireshark to look at the xml being sent to the server only a value for v_string is being sent as part of Class1. I'm guessing this is because it considers the value of v_integer to be null/not set. Here is an example of the client code.
Dim MyService as New Service1.ServiceClient
Dim test as New Service1.Class1
test.P_integer = 1
[code]....
how different types are passed/used since Integer is a intergral type and String is a class, but can't seem to work out what to do to fix the problem.
I am trying to write a linq statement that would take two integers and compare them, if they are not alike then it would select a name from a database. I have ho idea how to write this and i have already tried a statement with <> and it didn't work.
View 5 Repliesanything wrong with using datatype object and determine datatype in class property? I have a typed dataset and it has several integers columns that are null in the db. and when I make a call it throws exception.is there anythign wrong with setting it as object in my dataset.. changing the throw exception property to Nothing and passing it to my property as integer?
for each row in myDS.DataTable
cRate.CustID = row.CustID
next row
and in my class
Public Property CustID() As Integer
Get
Return _custID[code].............
i have a form with 12 text boxes. I'm trying to get the data from those text boxes to "save", and when that form is opened again have the data be inserted back. This form has different time slots so I need to be able to have it save and repopulate based on what time slot I am clicking on. I was going to have it read the data by splitting it with commas, then inserting them back into the correct fields but it's not working. I had it write the results to a text file and they get written correctly and inserted back, but the problem with that is it only reads that text file so every time slot I open up gets the same data. Below is code I used to get the data when the Save button is clicked. [Code]
Problem is I get an error saying "Char values cannot be converted to Integers" on the first line, the (","c) part. Plus even then I don't know if this would do what I want. EDIT: Ok I fixed the error and got it kind of working, but now I have a new question. Now, I put a button on the form that I can use to load the data when I choose to just to test. This works, it takes the data from each time slot and loads it back when I click the button. New question is how can I get it to load as soon as I open the existing appointment? Putting it in the form load event won't work because it checks for data before there is any in there.
I have a form with 12 text boxes. I'm trying to get the data from those text boxes to "save", and when that form is opened again have the data be inserted back. This form has different time slots so I need to be able to have it save and repopulate based on what time slot I am clicking on. I was going to have it read the data by splitting it with commas, then inserting them back into the correct fields but it's not working. I had it write the results to a text file and they get written correctly and inserted back, but the problem with that is it only reads that text file so every time slot I open up gets the same data.
Below is code I used to get the data when the Save button is clicked. [Code]. Problem is I get an error saying "Char values cannot be converted to Integers" on the first line, the (","c) part.
I tried coding for an application that will display the positive integers, negative integers and zero entered in a inputBox. for some reason it keeps crashing down.here is my code. paging all visual basic professionals. [code]
View 6 RepliesI have the following query, I'd like to sum the NULL value also. Some TimeSheet don't records in TimeRecord and some tr.TimeIn and tr.TimeOut are NULL.The query select only TimeSheet that has reords in TimeRecord. How I can have it select everything, and sum up the NULL value as well. So, the SUM of NULL will be just zero.
[Code]...
I am creating an xml file with LINQ as follows...
Public Sub CreateXml()
Dim db As New MDataContext
Dim Customers = <gallery columns="3" rows="3">
[code]....
Could i mix local values with the ones returned from the LINQ query...Something like the following?
Public Sub CreateXml(ByVal **Col** As String, ByVal **Row** As String)
Dim db As New MDataContext
Dim Customers = <gallery columns="& **Col** &" rows="& **Row** &">
[code]...
I'm having trouble with a null result, when I compare the query it said I cant it give the following error "sequence contains no elements"
Dim existe = (
p In abc.Ventadetalles
Where p.idarticulo = txtArticulo.Text
[code].....
I'm trying to create a list of days(integer) from a list of dates(date).
I tryed to do this....
[Code]...
I've got a subquery that returns the most recent value from a child table. In some cases the subquery returns nothing. The query below fails at runtime because the inferred type of MemberPrice is decimal and is not nullable. [code]...
View 4 RepliesI have a XML xElement like[code]...
In order to get rid of Trick nodes where value is null, I wrote:
myXmlElement.<Play>.<Trick>.Where(Function(m) m.<Trick>.Value = "").Remove()
I'm having trouble figuring out what to do with the bolded part, when there are no nodes to return.If there are no image tags inside the <images> tag, i get an "Object reference is not set to an instance of an object".I have been searching and searching for an answer but can't find one.
Dim orders = From o In xmlLinq.Descendants("order")
Select New With { _
.orderID = o.Attribute("id").Value, _
[code].....
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")
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've got what I think is a working left outer join linq query but I'm having problems with the select because of null values in the right hand side of the join.[code]I want to return all of e and one column from c called tClassCode. I was wondering what the syntax would be. As you can see I'm using vb.net.[code]If i remove the c.tClassCode from the select the query runs without error. So i though perhaps i needed to do a select new but i don't think i was doing that correctly either.
View 2 RepliesI've got a table that caches calculated values for certain dates. I want to use LINQ to select all rows where the calculated value fields are null.But when I use isNothing I get an error that LINQ can't translate this into T-SQL. Is there a way to select null values with link, like this...?
Dim var = From rec As Record In myDataContext.Records Where IsNothing(rec.calculatedValue) Select rec
Other posts on stackoverflow mostly discuss how to avoid or check for null values with LINQ.
Note: I can't just set cacluatedValue's default to -1 to flag records whose calculated value has not been set (and then select those records) because I run queries that sum/average the calculated values. Selecting nulls seems cleaner and less bug-prone.
I have a simple query as below:
Dim sizings = From a In db.Sizings
Where a.Customer.ID = customer.ID
Select a
If sizings.Any Then
.....
The sizings.Any line is throwing a null reference exception. I thought I was meant to use .Any to determine if there were any rows returned?isnothing(sizings) returns false.
Edit - Resolution:Don't use null objects in the LINQ Query!
Basically I have and array of integers that vary in size. I need to compare each number to each other number and display which number is repeated. For example:
Dim ints() As Integer = {1,2,2,5,4,6}
The number that shows up more than once is 2.
How can I run through the array and compare each integer with the numbers in the array. I tried a for loop but it didn't return the value I was looking for.
I've come across an error I'm not quite sure how to get rid of, I've got a listview with listview items making up the grid, I've got values coming from a database populating the cells however if there are any null values(in this case, there's null values in the date) it crashes my program. I'm not quite sure of a way to allow the listview to have null values in it, I figured it would default allow it but that's not the case.[code]....
View 1 Replieswhat is the code for allowing null values to appear on the textbox
Dim i As Integer
dg1.DataSource = bs
i = dg1.CurrentRow.Index
Patient_Profile.Txtpatient_id.Text = dg1.Item(0, i).Value