Pass Property To Create Filter Like LINQ?
Jan 6, 2011
I`m looking for a way to parse a parameter name like linq does.I want to filter before i download the date from the database.With LINQ the data is already red into a dataset. I only want to select data from the database witch i need. how i can send a property name to a function without using the property name as string and without to use to mutch code inside the function and without creating an instance of the object, etc.
Module
Module1
Dim user
As user =
[code]....
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Feb 6, 2010
I have a LINQ query:[code]How can I pass "MyField" to the Sub and make the LINQ "Where" clause work?
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May 22, 2011
Basically i have a list(of TransRecord)
vb Public Class TransRecord
Public TableName As String
Public PKs As String
[CODE]...
And want to create a linq filter to select only unique records for TableName + PKs (group by) ... but want it to select only the record with the highest ID for this group by.
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Apr 19, 2009
I am currently learning VB.net but for a project I need to create and array and pass it using a property. The data to be passed will be a train's destination, the time its due and the expected time of the train. I was wondering if someone could simplly explain how to first produce an array and then show how to pass it to a custom control
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Apr 4, 2012
The problem is: I have a list of objects, with some containing the same PlanId property value. I want to only grab the first occurrence of those and ignore the next object with that PlanId. The root problem is a View in the database, but it's tied in everywhere and I don't know if changing it will break a ton of stuff nearing a deadline.
So, if I have a list of PlanObjects like such.
Plan1.PlanId = 1
Plan2.PlanId = 1
Plan3.PlanId = 2
Plan4.PlanId = 3
Plan5.PlanId = 4
Plan6.PlanId = 4
I want to take a sub-list from that with LINQ (italics mean an item is not included)
Plan1.PlanId = 1
Plan2.PlanId = 1
Plan3.PlanId = 2
Plan4.PlanId = 3
Plan5.PlanId = 4
Plan6.PlanId = 4
For my needs, it doesn't matter which one is taken first. The Id is used to update a datsbase record.
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Sep 10, 2009
Example-I have a person class
Public Class Person
Private _fname As String
Public Property Fname() As String
[Code]...
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Jan 29, 2012
How would I implement a simple low pass filter in VB.NET? I have a byte array of 8-bit sound values sampled at 44.1 KHz and I would like to apply a crude and simple low pass filter that starts to roll off around 2.5 KHz. Nothing fancy - I'm not expecting lots of dBs per octave, just something to slightly reduce unwanted HF components. When I Google this all I seem to find are complex FFTs and other functions derived from electronics design packages that are way beyond my math to have any chance of adapting them for VB.NET.
I have tried some very crude averaging: take sample 0 and sample 2, average them and put the result in sample 1. It sort of works but is probably a bit too crude.
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Oct 9, 2010
I've been trying to add a database to my interface, and i can't seem to filter the data, i want to search based on last name and only display people with the that last name (the last name will be entered in a search form).I've tried writing SQL Queries but I can't seem to pass the variable that that holds the last name into the SQL Query, to filter the data.
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May 3, 2011
Public Sub adjectAllNormals()
Dim qry As LinkedList(Of CElement) = From elm In Elements
From id In SelectIDs()
Where elm.ID = id
Console.WriteLine(qry.Count)
End Sub
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Jul 12, 2011
I'm trying to filter out the time which is greater than 8:00 am and store it in array . Can anyone give me some suggestion?[code]
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Jun 17, 2011
I'm develloping a small application over na Access 2007 database. how can i pass the value of a combobox to a query being built with the query builder tool?If I use ? in the Filter column I�m prompted to enter the value but what I need is to pass the value of a combobox in a form. I tried to use:
HTML
=MyForm.MycomboBox.Value
but it is ignored, interpreted as the value to be filtered.
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Oct 1, 2009
I have a list(of t) and I got a iqueryable(of a)
I want to filter out any item from the iqueryable(of a) where a.id = t.myotherid
I'm not really sure how to write this query[code]...
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Dec 11, 2008
I am trying to grasp using Linq to read and filter xml files. I've been googling and trying all day long but still not successful.[code]
1. Firstly I want to select a contact with a certain node value, my code looks like this:[code]
2. The third level nodes have some same descedants child elements. Is it possible to sort the entries by <contactId>? How can I do that? For example I want to have a result like this:[code]
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Oct 4, 2010
Imagind I have the following in VB:
function doSomething()
From ou In ctxt.Users.Where(Function(p) p.UserName = username)
...
end function
how can I send the filter as parameter (something like below)?
function doSomething(filter as whatTypeHereAndHowToInstantiateInCallingFunction)
From ou In ctxt.Users.Where(filter)
...
end function
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Nov 2, 2011
I am trying to write a query for an existing database, I am using LINQ on EF3.5 inside VS2008 as that is the only environment available to me.I have a starter query that gives me a list of items so the user can select what they want.
"e.Result =
From c In MLDb.TBL_FeatureInfoSet
Order By c.INSP_ROUTINE_NM
Select c.INSP_ROUTINE_NM
Distinct"
The user can then select from the list one or several items they are intersted in and i want to use these as the filter in a further database call. It's not then difficult to have a where to filter on one string however, I would also like to be able to allow the user to select several items from the list box and the data for all of those to be returned.
[Code]...
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Sep 1, 2010
I am wondering if it is possible to filter data from a datatable.Sample datatable
Quote:
Sno CatID Nos
1 XYZ 25
[code].....
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Jan 23, 2009
how to set up the filter property to look for more than one file type? msdn says we can set the filter to '*.*' or *.txt' etc, but doesn't say how to specify more than one type.I've tried a pipe delimited string but it didn't seem to work e,g '*.txt |*.log|*.xml'.
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Feb 3, 2010
I've got a datacontext and created a binding source using LINQ to sql but cannot filter said bindingsource. The supportsfilter of the bindingsource is set to false ? why ? I can't find any info to say that I cannot filter a binding source based on a linq query.[code]
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Nov 8, 2010
OK I have a base query that is returning a list (ObjectQuery, actually but I don't think it matters) I have about 5 subtypes based on the main type and I need to filter them. Everything works fine until I want the results to be of the main type (not a subclass) Basically I have a query that includes everything, then I filter out the types that are not checked in a checkedbox list. (asp.net) Lets say I have an Entity named Task, and SubTask1 and SubTask2 that inherit from Task
[Code]...
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Jun 30, 2011
Could not find this through Google or in SO questions.I have a checkbox listbox on my form. I want to filter my List by the list of selected Ids from that listbox that are checked, in SQL I would have done this like "Where TypeId In (1, 4, 5, 7)"... how do I do that in LINQ?
I feel like I am missing a really obvious answer, but cannot get it.
For argument sake... here is the what I have for sample data:
In Colors (List<of currentColors>)
ID, Name, TypeId
1, Red, 1
2, Blue, 1
3, Green, 2
4, Pink, 3
Selected Types 2 and 3 in CheckboxList: filteredColors
[Code]...
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Aug 27, 2011
The code below is used in a Linq to SQL solution, and is in the Load event of a form. It works fine to display an ordered list of people's names, and set the value member to that person's ID. However, I'm going to be using these 'people' comboboxes a lot, so I'd like to put a sub into my Utility code there is only one line in the form's Load event.
I want to call something like: Call ComboboBoxPeople(cbo, tblTurnbackMain, ReportedByID)
The sub would begin like: Public Sub ComboboxPeople(cbo as Combobox, tbl as 'sometype', fld as 'someothertype')
What can I use as the parameter types for tbl and fld?
[Code]...
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Nov 19, 2010
I'm having trouble with VB LINQ syntax. I have a web service that is returning JSON to jQuery and I need the index of the items but can't figure it out. [code]...
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Jul 30, 2010
This is a theoretical question, I've already got a solution to my problem that took me down a different path, but I think the question is still potentially interesting.Can I pass object properties as delegates in the same way I can with methods? For instance:
Let's say I've got a data reader loaded up with data, and each field's value needs to be passed into properties of differing types having been checked for DBNull. If attempting to get a single field, I might write something like:
if(!rdr["field1"].Equals(DBNull.Value)) myClass.Property1 = rdr["field1"];
But if I've got say 100 fields, that becomes unwieldy very quickly. There's a couple of ways that a call to do this might look nice:
myClass.Property = GetDefaultOrValue<string>(rdr["field1"]); //Which incidentally is the route I took
Which might also look nice as an extension method:
myClass.Property = rdr["field1"].GetDefaultOrValue<string>();
Or:
SetPropertyFromDbValue<string>(myClass.Property1, rdr["field1"]); //Which is the one that I'm interested in on this theoretical level
In the second instance, the property would need to be passed as a delegate in order to set it.
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May 29, 2010
I'm fairly sure this is possible, but what I want to do is have a generic method where I can pass in an object along with a Expression that will tell the method which Property to use in it's logic.Essentially what I would like to code is something like:
Dim firstNameMapper as IColumnMapper = new ColumnMapper(of Author)(Function(x) x.FirstName)
Dim someAuthorObject as new Author()
fistNameMapper.Map("Richard", someAuthorObject)
Now the mapper object would know to set the FirstName property to "Richard".Now using a Function here won't work.
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Jan 24, 2010
I am trying to pass a lambda function to Linq's orderby and cannot get it to work.
The relevant code is:
Dim myordering = Function(m) m.Count
If isAlphaOrder Then
myOrdering = Function(m) m.Key 'Order by Alphabet
[Code].....
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Nov 14, 2009
I am using the following line of LINQ to drill down into an element. Is it possible to expands this code to drill further down so that I can add content to the <population> element in "Test2". I want to be able to do somthing like element.SetValue(1000000). However I need to expand the code below so that I can pass the entire query results into the variable called "element"'
Dim eles = From c In doc.Descendants("File") _
Where c.Attribute("Name").Value = "Test2" _
Select c
[code]....
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Jul 11, 2011
How can I pass stored procedure name dynamically to Linq-to-SQL, vb.net and get the result into a datatable.
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Aug 9, 2010
I'm setting up a simple helper class to hold some data from a file I'm parsing. The names of the properties match the names of values that I expect to find in the file. I'd like to add a method called AddPropertyValue to my class so that I can assign a value to a property without explicitly calling it by name.The method would look like this:
//C#
public void AddPropertyValue(string propertyName, string propertyValue) {
//code to assign the property value based on propertyName
}
'VB.NET'
[Code]...
Is this possible without having to test for each individual property name against the supplied propertyName?
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Oct 24, 2011
I'm trying to pass some values to another page and I have the values in List (Of String). However, I'm getting an error (at design-time in the IDE) saying: There is no member "X" of System.Web.UI.Page. I was able to get the Property through Intellisense. So I'm not sure why I'm getting the error.
Here's the code:
[code]...
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Apr 27, 2010
I am having trouble to retreive a Image Raw Data into a Property, I included the related function and the Property.
The error I got is:.ImageRawData = CByte(dr.Item("ImageRawData"))
Error Message:Value of type 'Byte' cannot be converted to '1-dimensional array of Byte'
Public Function SelectOneImage() As ImagingData
Dim adapter As New DataAdapter
Dim ds As New DataSet
[code]....
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