Dynamically Reference An Object Property Using A String?
Jan 21, 2011
I'm trying to reference a public property from a string. How can this be done in vb.net?I have the text value of "FirstName" stored in strucParam(i).TxtPropertyName.[code]...
I am trying to make an app that interfaces with Salesforce. Now within salesforce you can customize your database to have any tables or fields that you want/need What I am trying to do is once I do my query, salesforce has your query results returned as a salesforce object. My app basically manages info in salesforce based on rules, sometimes people may need to customize those rules based on fields in the database, however because I dont know what kinds of fields are in their particular database I need to do it programatically...
SO what I want to do is reference the objects property via a string text property name... i.e. if they use a field called "IsFromLebanon" as a boolean I want to be able to access QueryResult.IsFromLebanon. but since I dont know if that field exists or not I dont know how to access its property without spelling out each time. I know clearly thats not going to work, but I dont know how to access the property name without KNOWING the property is going to be there, does that make sense? I dont know if I am making sense or not, it makes perfect sense in my head
I'm checking If a border's child property is not set to nothing or equal to a given element, but whenever I run the program, it says that it's set to nothing and crashes. Here's my code:
If Not Me.Child.Equals(Nothing) Then ... If Me.Child.Equals(value) Then ...
Both gives an error. What should I do to pass these lines? Also in C# it would look like this:
if(this.Child != null) ... if (this.Child != value) ...
I have a class library that contains a number of classes. I would like to dynamically create an instance of one of these classes, set its properties, and call a method.
Example:
Public Interface IExample Sub DoSomething() End Interface Public Class ExampleClass
I have a class that has a property that I declare like this:
VB.NET Private _DirectoryList As List(Of FileDirectoryInfo) ''' <summary> ''' Array of directories. ''' </summary> ''' <value>Object</value> ''' <returns>Directory array list</returns> ''' <remarks>N/A</remarks> Public Property Directory As List(Of FileDirectoryInfo) Get Return _DirectoryList End Get Set(ByVal value As List(Of FileDirectoryInfo)) _DirectoryList = value End Set End Property
I would like to format output to a property of a custom control I have made.For instance I have a literal control in my control and when populated I want to check if it is longer than 30 characters long, if so, then go to the next space (as to not cut the word off) after the 30th character and place a <br /> tag in to place the next 30 characters on the next line.So if there were 100 characters in a string, there would be 3 line breaks in the label.I have the looping worked out to get the label populated but cannot get how to dymaically create the array based on the string lenth property and index of method.
This is something that has been bugging me for a while as it is easily fixed but not desirable.I have a DataGridView that has 5 columns. The first is called ID.In vb.net the following line gives an error "Object reference not set to an instance of an object": dgvJobs.Columns("ID").Visible = False ' ERROR dgvJobs.Columns(0).Visible = False ' OK
Obviously using the name is much better than a hard coded value to reference the column but wondering if there is anything i can do to get this to work correctly?The datagridview datasource is BindingSource control with the datasource being a dataset.
MVC 3 razor VB.NET project. I have resorted to manual building a list for a drop down box so I can insure certain values are available in the select list and also to control what the first item is in the list. The below is my code snippet for the part that is giving me problems..
I want to make a hashtable of object references and I want a different object's reference to be the key. How can I do this in vb.net? In java (assuming I am using the default toString method and that add() takes a string as a key and an object ref as the value) this would be something like: hashtable.add(obj1.toString(), obj2)
I do not want to use a vb.net gethashcode() function because I want deep clones of objects to have different identifiers. A related question is what is the default toString in vb.net? How can I get a string that represents an object reference in vb.net?
I get an error at the ReadContents(0) = FilePath line saying "Object reference not set to an instance of an object", but the message box shows that "FilePath" holds the file path string.
We have an object with properties, and a a SQL database we're reading in, to create a list of objects, with columns corresponding to each property.if a column is missing from the database (e.g. caused by an outdated version of the database), we want to assign a default value to it.I've created a dictionary, mapping the column name to its default value (both strings).However, I was wondering if it was possibly to somehow convert the column name (string) to an object property (e.g. the string "name" to AnObject.name?), as the property and column name are generally the same.I tried to use GetType().GetPropert("column name"), but I can't seem to do assignments through that)Alternately, is it possible to somehow create a dictionary, storing the object property as the key (and the column name and default value in a struct), and then grabbing it after.?
String s = "test"; String is a class, so to use it we should create an object of it. But rather we just make a reference of it and give it a value. How is it possible and what concepts are used in it. The metadata of String class shows the following :
I'm using FileHelper to generate object's property. Here is an example of one property:
<FieldOptional(), _ FieldTrim(TrimMode.Both)> _ <FieldNullValue(GetType(String), " ")> _ Public StoreNo As String
As you can see the StoreNo will either have a value or " ", one of the business policy is to check if the StoreNo is empty or nothing if the object's StoreNo is empty or null then the record will not create.
I though about creating an HasValue Function in the class to check the StoreNo and other properties in the object but I feel like it is a hack.
Public Function HasValue() As Boolean Dim _HasValue As Boolean = True If StringHelper.IsNullOrBlank(Me.StoreNo) Then
[Code]....
I don't think this approach is an ideal solution. what if the StoreNo is remove or change to something else. What's the best approach to check object's property?
So I've run into a case where I have a class that can store either a string or a numeric value, and I want a single property to return one or the other (it would be a failure for both to be set). I'm using a custom generic class to deal with the numerics (so I can use signed, unsigned, and nullables), and will be storing the string in a separate variable.
In theory, if overloading could be done based on the return type, I could do this quite easily. But .NET currently disallows this. So I am wondering if there is some other really-far-out-there trick (outside of MSIL generation via Reflection.Emit) that could accomplish the same thing.
I'm open to ideas via delegates, pointer dereferencing, generics, mystical rites, etc. Also interested in any thoughts or pros/cons of such possibilities as a learning tool. If using a standard Object is the only way to achieve what I want, then that's fine with me. But It's difficult to find the correct set of keywords to hunt down this kind of capability on Google, so I thought I'd ask here before I moved on to doing something else on the project.
The book "Beginning ASP .NET 4 in VB 2010" contains the following:NOTE: TaxableProduct inherits from Product.You can also cast in the reverse directionfor example, cast a Productreference to a TaxableProduct reference. The trick here is that this
I am using the IndexOf function of the string class to find a specific instance of a string. And based on that I have a logic to do something. Below is the example of what I am doing. The code is in production and is working fine. But for some instance I am getting an "Object reference not set error". Yeah its intermittent.The requestXML is a string of xml data passed in as a paramter to a subroutine. I am fetching the xml string as a form post in a request object. The only thing I could think of getting this kind of error is when the requestXML string varia
requestXml = Request("requestXML") SubmitRequest(requestXml) Private Sub SubmitRequest(ByVal requestXml
Private Sub SpellChkMenuItem_Click(ByVal sender As Object, ByVal e As System.EventArgs) Handles SpellChkMenuItem.Click Dim activeRichTextBox = TryCast(Me.ActiveControl, RichTextBox) 'clsFS.CheckSpelling(activeRichTextBox)[code]....
When I am in the rtb and click on spell check button it tells me the error "Object reference not set to an instance of an object." On this line
SpellChecker.Text = activeRichTextBox.Text
But it is suppose to be getting the focused rtb correct? So why is it not referenced
I am receiving this error: Reference to a non-shared member requires an object reference on the code I've bolded within the code body. Here is my code:
I get this error:Reference to a non-shared member requires an object reference.When i compile on the following code section:
Private Sub statusBarToolStripMenuItem_Click(ByVal sender As Object, ByVal e As EventArgs) ToolStripMenuItem.Checked = Not ToolStripMenuItem.Checked statusStrip1.Visible = ToolStripMenuItem.Checked
I am opening frmB (variable for FormB - the actual form) from frmA. From btn1 I open frmB like this:
frmB = New FormB() frmB.Show()
From btn2 (frmB is already open) I bring frmB to the front from behind frmA:
FormB.Show() FormB.BringToFront().
No problem so far. Now I need to pass an arg to frmB. This is where I am having the problem.
from btn1 (in frmA) I do this:
frmB = New FormB(myArg) '--pass myArg to constructor of FormB -- no problem here frmB.Show()
then from btn2 -- this is where I have the problem
FormB.Show() FormB.BringToFront()
I tried placing myArg in FormB.Show(myArg) but that did not fix the problem. What is the correct way to pass myArg to FormB (frmB) in this scenario? Do I need to share FormB or frmB? How do I do this? "frmB" is frmA level variable.
why i am getting an "reference to a non-shared member requires an object reference" error on format.Yesterday gets the previous days date and presents it in a yyyyMMdd format.vsettlementDates takes the "Yesterday value and requests data from it.
Dim Yesterday As String = format(Today.AddDays(-1), "yyyyMMdd") Dim vSettlementDates As String = (Yesterday)
Error 1 Reference to a non-shared member requires an object reference. (on WindowsIdentity.Groups)
Here's my code from that uses the WindowsIdentity.Groups property to display the identity references for the groups the current user belongs to. This code is part of a larger example provided for the WindowsIdentity class.
Public ReadOnly Property Groups As IdentityReferenceCollection Get Dim irc As IdentityReferenceCollection
I have the following code below, how the line where it says : For Each c As councillor In councillorList i get the error: reference to a non shared member requires an object reference. Can someone please advise where i am going wrong? [Code]
Alright, so im getting this error:Reference to a non-shared member requires an object reference.This is the bit of code the error is pointing to:My.Settings.Bookmarks.Add(WebBrowser.Url.ToString)Why is it giving me this error?Its saying WebBrowser.Url is the problem.
im sure it is something really simple. Im by no means comfortable with VB. The below code is not mine but i have altered it for my needs. However im getting a couple of errors.
Reference to a non-shared member requires an object reference. I have underlined the errors in the code and they all refer to the above description
Im trying to create a login page which accesses a mysql database I keep getting this error: reference to a non shared member requires an object reference