Is there a way to reference an object by using the value of a string read from a text file? Here's an example of what I mean: I have a user control called 'Fish', one called 'Cats', and one called 'Dogs' and so on.... I have a text file containing this line, amongst many others in a long script written after compile time by the user:
[Code]...
I have a label testlabel. is there some way I can refer to it as:
dim t as string = "testlabel"
(something here referring to the OBJECT with the same name as the string).text = "mytext"
? I have 50 labels with text to change and would love to be able to:
for i = 1 to 50
dim t as string = "testlabel" & i
convertsomehow(t, label).text = "mytext"
next
so that this would change testlabel1, testlabel2, testlabel3, ... , testlabel50.
I know the name of a textbox in string format: txtbox & i. Through the loop, the txtbox name will be txtbox1, txtbox2,.... And I want to change the txtbox & 1 's text dynamically in the code. How can i refer to the textbox obj from the string?
View 9 RepliesI hope the question makes sense, anyways. I'm looking to know if in VB.NET, when we call an object's constructor, is there some kind of a reference that points back to the caller? I'm interested because of a corner case where I want the object being created to first be able to validate the existence of some data in the caller before it allows itself to be created. If this validation fails, I plan on throwing an exception. This corner case will never happen at runtime unless the object being created is used improperly by a programmer. The object being created is not inheriting the object I want it to validate, so I can't do anything with the MyBase qualifier.
It's bit of a "future-proofing" issue that I have a (bad) habit of doing. Not critical -- I can always leave stern comments behind as a last resort. Wanted to know if this was possible.
Is there a possible way to refer an object through it's name in Vb.Net?The case is, I have menu items created in my designer with names such as MenuA, MenuB and MenuC.On the database, I created a table consisting the list of all available menus in string format : MenuA, MenuB all the way to MenuZ.
Also I created a dynamic table consisting the user permission, what menu is accessible by a certain user.So when I started the app, it will get the name of menu assigned to the logged user, and start to turn the Visible property to TRUE.If it was a Control, I would just loop through it by Parent.Controls.Find(FoundMenu, True).My problem is most of it is not a control, it is an Item added to the Control, or even another SubItem added to the Item.So how can I found an object in my UI only by it's name?
SearchQuery = "SELECT menu_name FROM tbl_menulist menu, tbl_user user WHERE menu.id_menu = user.id_menu"
QueryReader = ExecuteQueryReader(SearchQuery)
QueryReader.Read()
[code]....
I am doing a calculator project.In the given code below I want to modify the line txtDigitPanel.Text = Trim(txtDigitPanel.Text) + "0" as txtDigitPanel.Text = Trim(txtDigitPanel.Text) + this.text (the word 'this' is taken as a reference to the object that has invoked the event ) to avoid hardcoding. Because when I copy the BtnZero, the same code will work for other digits also. Is it possible?
Private Sub BtnZero_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
If Len(Trim(txtDigitPanel.Text)) < 15 Then
txtDigitPanel.Text = Trim(txtDigitPanel.Text) + "0"[code]....
after searching on the web, i know that Me keyword is use to Refer to the Current Instance of an Object, but if i want to Refer to the others Instance of an Object, what is the keyword that i need to use?
View 4 RepliesI'm using win7 64bit + express 2010. in the program, I need refer to Microsoft HTML Object Library. So, I added it, then I found, it can not be "copy local". I remeber it could before when I use oit on vista + 2008.
Now, the question is: how can I include it in the setup? since some users may not have this dll on their pc.
How do I refer to a form in my project by using a string variable? I'm running Visual Studio 2008.My main screen has a number of dropdown menus that, when an item is selected, a form will open:
Dim Mdi_frm_Doors As New frm_Doors Mdi_frm_Doors.MdiParent =Mdi_frm_Doors.Show()In this example, I am providing the name of the form directly (frm_Doors). What I would like to do is refer to the form as a string variable.I'm already doing something similar to access specific controls on other open forms (where str_Field is the name of the control I am accessing):
[Code]...
I have a string called testlabel, and would like to refer to it via the string "testlabel", how do I do this?
for instance:
dim testlabel as label
dim a as string = "test"
dim b as string = "label"
'what is the line I need here? a & b.text = "hello world"
to get testlabel.text to read "hello world"?
I have lots of labels that I need to refer to.
E.g. label1 = listbox1.selecteditem.tostring & "123"
label2 = listbox1.selecteditem.tostring & "123"
I have 20 labels which i need to repeat the same process for. What I found was this code which always gives me the null reference error.
CType(Me.Controls("Label" & i), Label).Text = "what i want here"
I have stated dim i as integer = 1
And later i = i + 1 until it is 20.
I've tried i.tostring and cstr(i) when referring to it but it keeps saying it doesn't exists even though i have labels 1 to 20 named label1, label2 etc. on my Form.
numberofchar = timefull.Length
If timefull = "" Then
Else
If numberofchar = 11 Then
timefull = timefull.Remove(2, 9) ' isolate the hour depends on number of digits in hour parameter
Else
timefull = timefull.Remove(1, 9)
End If
End If
This is my code, it doesn't work when I copy into form load. But when I try it in another form, it works. Index and count must refer to a location within the string. Parameter name: count
why this error happens with a bit of code i was trying? The code is actually intended to be for an onclick event, so it actually works there.
But im just curious as to why it errors as an onchange event. This is 9am pre-caffeine, so the reason is probably starring me in the face! On a form i have a text box, and a combo box. The combo box has various options in it, natch. Its a search form, which then fills a gridview with the results.
Drop down list options are: home number, mobile number, post code, Name, DOB
I thought id try and be "clever" and do away with the need for the combo box. Since a mobile number begins with "07", names are just characters, postcodes are character character number, and home number is all numbers and doesent begin with "07", and date of birth has /'s in it.
So i tried this to test the idea:
Private Sub AppSearchTB_TextChanged(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles AppSearchTB.TextChanged
Dim TLength As Integer = 2
[Code]....
I am trying to get the first 50 letters, so I used the subString function to get it. As you can see, I used this code to get it:
<%# Eval("BannerDescription").ToString.Substring(1, 50)%>
But unfortunately it's not working and an error message is coming up:
Index and length must refer to a location within the string.
Because the user is the one who is controlling the data entry! Some times he gonna enter 10 letters other times maybe 1000 letter?
I tried them all but can we use it this way :
<%# IIf(Eval("BannerDescription").ToString().Length > 49, Eval("BannerDescription").ToString().Substring(0, 49), Eval("BannerDescription"))%>
I was trying to make a simple program to search in my mysql db, but i'm seeing this error :{"Index and length must refer to a location within the string. Parameter name: length"}[code]
View 4 RepliesI keep getting the error saying that index and length must refer to a location within the string.
Public Class MainForm
Private Sub btnAdd_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnAdd.Click
Dim description As String = String.Empty
Dim invCount As String = String.Empty
[code]....
Dim Phone as string = "478-742-4050 478-256-6550"
If _Phone.Length > 25 Then
_Phone = IsNull(ReturnValue.Substring(0, 25).ToString, "")
End If
Return _Phone
Error: "Index and length must refer to a location within the string. Parameter name: length"
why error "Index and length must refer to a location within the string."appear when the process of the program is going to executeNonQuery, i'm looking the error for 2 day's i still can't find it.
[Code]...
I got this error and I don't know what should I do. Index and length must refer to a location within the string. Parameter name: length That's the line that i get the error on:
[Code]...
why when i upload less than 10 item the program do but more than it like 15 and above the program give me error saying "Index and length must refer to a location within the string."
here is my codes below
For Each myDatarow In tblLocal.Select("sync ='0'") '
' tblServer.ImportRow(myDatarow)
' dataimpt = myDatarow.Item(4).ToString
[Code].....
the error appear when the program is going to update the 14th data... meaning from 1st to 13th data program works in the 14th it's not it gives me error "Index and length must refer to a location within the string
I'm working on a vb.net project, when I execute the project I get the following error message: "error message: index and length must refer to a location within the string"
Public Sub New(ByVal lineIn As String)
parent = Trim(lineIn.Substring(0, colStarts(1)))
enfant = Trim(lineIn.Substring(colStarts(1), colStarts(2) - colStarts(1)))
des_F = Trim(lineIn.Substring(colStarts(2), colStarts(3) - colStarts(2)))
[Code]...
I get the error msg in the line marked bold. When i checked the input file, the length of all the fields looks fine. I dont understand the cause of this error.
this is not working?
[Code]...
End WhileI am trying to read from the ": " to the end of the line. I keep getting this error: Index and length must refer to a location within the string. Parameter name: length
am getting the above exception while swaping Items in the list(lstRoutePriority).PFB my code
if (lstRoutePriority.SelectedIndex > 0)
{
//Swap the two items
[Code].....
Under component services, a COM+ component is used by the company, right-clicking it and choosing 'Activation' tab will show the 'constructor string' that is used for DB server connection by all applications. How can I access it the simplest way possible?
[Code]...
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
[Code].....
I'm trying to setup a WCF web service to be consumed by JavaScript using JSON and jQuery.I've noticed that you can send JSON without a DataContract if the service method parameters match the naming structure of the JSON object:
<ServiceContract(Namespace:="http://foo.com/bar")>
<AspNetCompatibilityRequirements(RequirementsMode:=AspNetCompatibilityRequirementsMode.Allowed)>
[code]....
Dim db As New DataClasses2DataContext
Dim newvet = From n In db.vets Select n.vetid Distinct
(Label1.Text = newvet.Count.ToString)
this is the error message I am getting:Object reference not set to an instance of an object.
dim myCollection as new Specialized.StringCollection
dim myFoundThings as new ArrayList
dim index as Integer
dim newResultMemberName as String
[code]....
This is part of some code that will run without user interaction once it's spinning away, and I need to create a unique object from some items found in a StringCollection, naming the objects using information found in the strings stored in that StringCollection.
"Index and length must refer to a location within the string. Parameter name: length" whenever I run this code
[Code]...
If using the following in an if statement I get an error: If trg.Name.Substring(4, 6).ToUpper <> ("ABCDEF") Then I get the error: "Index and length must refer to a location within the string. Parameter name: length"
I assume this is because the string (trg.name) is too small for the 4, 6 substring. What would be the correct method of working around this problem? VB.net Studio 2008.