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 RepliesIs 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:
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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.
Suppose I have a label control on a windows form called "UserName". How can I refer to that label programmatically using the label name? For example I can do:
For each ctrl as Control in TabPage.Controls
If ctrl.Name = "UserName" Then
' Do something
End If
Next
This seems quite inefficient. I would like to do something like: TabPage.Controls("UserName").Text = "Something" I did some googling but couldn't find a satisfactory answer. Most suggested looping, some said .NET 2005 doesn't support direct refenece using string name, and FindControl method was asp.net only...
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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):
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In VBA from Access 2003 I was able to employ the following :Form.Controls(" in here I am able to use a string variable holding the name of the control I want to reference ").property= etc.Is this kind of thing possible in VB .netI have a listview control to which I am adding 'errors' and the tag property of each item hold a string that is the name of the control I want to set the focus to when they double click on the listview item. So I want to do something like this :<listviewitem.tag>.focus()and have the string interpreted as a control name.
View 5 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.
I have a solution with several Projects in it. There is a Windows App project (called ImportClient), and a Class Library (Import.Library). The Import.Library has functions to perform data imports (I have other applications in the solution that also need to call it). But the interactive application, I want to be able to pass in some form controls, and have it update the GUI. No problem. But, I also want to execute a DoEvents() so that the loop execution doesn't hang other interaction to the app.
So, ImportClient has a reference to Import.Library. But I can't add a reference to ImportClient to the Import.Library, because the compiler complains about circular reference, etc. I don't know how else to define the My.Application object of ImportClient as a parameter to the data function in ImportLibrary.
(I realize this is a dumb question - problem is, for this project I have a tight timeline, and haven't learned how to do the BackgroundWorker process. If you think I could pick it up quickly, I'm open to some hints about how to update the progress bar on the GUI, and how to pause / cancel the background task.)
I am getting this error "Object reference not set to an instance of an object" and I dont know where/how to fix it and it does not tell me where the error in the code occurs, just a pop-up windows saying the error. Here is the code on the "start up" Windows form..
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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()
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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.
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
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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 am missing something simple. I know how to bind asp.net datagrids and webforms, but this is my first time trying to bind to an object list of T in a windows form. (I am use to using datasets with datatables and im trying to get away from doing that).I have a simple object list that gets populated on the form load. However if I click a button to add a dummy record the datagridview does not display the new record added. The bindingNavigator (if clicked nextrecord) and "debug stops" all show that the new record I just added to the object list is there.
Even adding the datasource object in the watch list shows the new records are there. They are just not displaying.
I cannot seem to figure out as to why the new record is not being displayed in the datagridview when I can see the record got clearly added to the datasource.
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I 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"
i would like to copy the inputs of the textbox in my main form to another users form.
View 2 Repliesi need help on this simple case [code]How could i do 'that bold area'? xString actually was dynamic variable i got from Database with SQL syntax.
View 4 Replieswhy 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.
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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:
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I want to insert a Windows Media Player object in my Form, but I have not the control on my Toolbox.
I have done the steps:
Right-click
the Toolbox -> Choose item -> COM Components -> add Windows Media Player component
(which references to C:WindowsSystem32wmp.dll)
But there is not the control on my Toolbox.
In my project references I see "MediaPlayer" into "Imported namespaces" and it is checked. In the references window it is also present "Windows Media Player". Where is the error?
I have a string value of form names in my DB so when my condition passes, the variable string will take over the value , then that value will call the form(variable) as string.
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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
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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)))
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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.