VS 2008 Form' Is A Type?
Jan 24, 2012'form' is a type in 'WindowsApplication1' and cannot be used as an expression.
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VS 2008 Have A User Type Something Into A Text Box On A Form?
May 15, 2010I'm looking to have a user type something into a text box on a form and then on button press check that against values held in a single column of a single table in a database that I already have linked to the project. If it finds the item in the table Do X if not Do Y?
View 2 RepliesVS 2008 Dragdrop - Check If The Present Data Type Inherits From The Base Type
Aug 20, 2009I have a number of controls (Device1, Device2, etc.) that all inherit from BaseDeviceControl. In the DragEnter event handler I am trying to test for the correct type by using the BaseDevvceControl like this....
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VS 2008 : Error: Conversion From Type 'DBNull' To Type 'String' Is Not Valid
Jun 15, 2009how can I solve this error without having to fill all of my fields. Some of the fields in my database are Nulls and some have records.
Error: Conversion from type 'DBNull' to type 'String' is not valid.
VS 2008 Unable To Cast Object Of Type FrmChild1 To Type FrmChild2
Dec 8, 2010I have 2 Child forms inside a parent. For example, FrmChild1 contains a "Friend Sub" I wish to call.I would like one of the child forms to call that sub from another child form (we will call it FrmChild2. The following code works, but when it's done going through the "For Each", I get a "Invalid Cast"
' THIS CODE IS IN FrmChild1
For Each mFrmChild2 As FrmChild2 In FrmParent.MdiChildren
mFrmChild2.GuestRefresh(False)
Next
Error after calls are made:"Unable to cast object of type FrmChild1 to type FrmChild2.
VS 2008 : Error - Unable To Cast Object Of Type 'ObjectCollection' To Type 'System.Array'
Feb 24, 2012I am using a background worker and am attempting to use the following code. However I keep getting this error on i "Unable to cast object of type 'ObjectCollection' to type 'System.Array'."
Private Sub btnVerify_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnVerify.Click
myArray = listProxies.Items()
BackgroundWorker1.RunWorkerAsync()
End Sub
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VS 2008 - Conversion From Type 'GridViewRow' To Type 'Integer' Is Not Valid
Sep 8, 2009I'm creating a login system with ASP.NET and VB.NET, and I have the webpage read a MySQL database for a table with the usernames and passwords. In the 1st column is an auto-incrementing id number, 2nd is their username, and 3rd is the password. Here's the code I have for searching through the table (which is a GridView named "logintable"), but I get the error "Conversion from type 'GridViewRow' to type 'Integer' is not valid. It seems like this code should work, so what's wrong? [Code]
View 2 RepliesVS 2008 - Conversion From Type 'InternalField' To Type 'String' Is Not Valid
Jul 9, 2009We get this error: Conversion from type 'InternalField' to type 'String' is not valid. When we get to this in our Dim fname2 = fname args.Graphics.DrawString(fname2, New Font("arial", 8), Brushes.Black, 5, 5) fname is a nvarchar variable from a recordset. It's just a name.
View 8 RepliesVS 2008 : Conversion From Type 'DBNull' To Type 'String' Is Not Valid
Jan 20, 2010I use following codes to retrieve data from table, but get error Conversion from type 'DBNull' to type 'String' is not valid.
str = "Select * from gpass where vou_no= " & Val(Me.txtGat.Text) & " And Date = '" & Me.txtDat.Text & "'"
dt = GetTable(str)
If (dt.Rows.Count > 0) Then
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VS 2008 Conversion From Type 'DBNull' To Type 'String' Is Not Valid?
Apr 29, 2009I am importing an Excel spreadsheet, turning it into a dataset and inserting the results into SQL Server (only 100 rows).
I am having an issue with one of the date columns in Excel, which can have a value or not. The "F" column is the one that may be blank and this is the error I get: Conversion from type 'DBNull' to type 'String' is not valid.
How can I add a check to the Dim F As Date = CDate(row(5)) to handle a null?
VB
' The use of letters instead of
' more descriptive variables is
' strictly for this sample peice
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Take A Selected Aircraft Type From A Previous Form And Put It Into The Form?
Aug 11, 2009Dim Type As String = frmFrontEnd.cmbModel.SelectedText.Substring(0, 4)
cmbType.SelectedText = Type
i would like to take a selected aircraft type from a previous form and put it into the form i am working on at the moment, but i want to edit the string so it only has 4 characters.I thought the above line would do it but apparently not. the error is to do with the length.An example:the model in 'the other' combobox is A330-200/-300 and i would like to put A330 into the new combobox cmbType in the above code.
VS 2008 Pointer - Error32'System.Reflection.Pointer' Has No Type Parameters And So Cannot Have Type Arguments
Jul 15, 2010I have an open source project I converted to vb.net. I solved all the errors, except for one. This is the C# line
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VS 2008 Unable To Cast Object Of Type 'System.String' To Type 'System.IFormatProvider'
Oct 20, 2010I have a bit of trouble right here, I am trying to get the data from the site and input them in the listview. Well, when my main app start to load through on debug, then it start to display a warning. The warning is: Unable to cast object of type 'System.String' to type 'System.IFormatProvider'.
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VS 2008 - User Can Retrieve Value In Any Numeric Array Type Rather Than Specifying An Array Type
Aug 11, 2011I am writing a scripting language which used .net for execution. Now I have written a function which accepts an object and return a set of numeric values. I wanted user to pass any numeric array (e.g. integer,single,double,long) and I could return values in that format. I mean user can retrieve value in any numeric array type rather than specifying an array type. E.g.
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Get All The Controls Of A Particular Type In A Form?
Jul 12, 2010Is it possible to get all the controls of a particular type in a form without using any loop and without iterating all the controls (recursively or not depends upon the design of form).
I have the issue with loop is: there are a lot of controls in my form (more than 500) and it is taking a lot of time in executing the function
Opening Form By Type Or Name
Jul 17, 2003How to create an instance of a form if it is not know in advance which formtype has to be opened. If you want to skip the chitchat: the .NET code example is at the end of this post. First the Symantec: when we create a new form, this form has a name. If we refer to that name, we actually refer to the name of the type of object that is just created. When to use of course when reading the subject you might think: why not just pass the form to a parameter that takes a form (or control/object)?
The answer is: you don't when it is not sure, when or if a new instance of the object has to be created or, as mentioned, when the procedure is called it is not known which class has to be created. You could of course hold a bunch of created objects, but that would be a shameless misuse of memory. Imagine the following scenario (seen something like this in a post, but can't find it anymore):
You have a class that is able to trap an event, say the doubleclick of a textbox, and has to open a form when it occurs. If it's always the same form, that's easy, but what if you want it to be determined during runtime? This is a quite common story: doubleclick on article opens the detail form of that article, doubleclick on supllier opens that particular form. If you use a form variable, how do you say to the class which form should be opened? This will not work
Code:
Dim FormToOpen as Form 'you don't want to open it right away, you want to know when the time comes what form to openFormToOpen = Form1You could say FormToOpen = new Form1, but then 1. an instance would be immediately created, even if it never will be used: memory leak. 2. you can never close the form, you'll always have to use the same instance created when setting the form. Consequently, you can never open more than 1 instance using this way.
The solution: use the type. If you know the type, the Activator class will enable you to open (and return) an instance of that form at any time and as much times as you like. (The Activotor class exposes the function CreateInstance which returns an instance of the specified object)The following code creates an instance of the type form1 and shows it.
Code:
CType(Activator.CreateInstance(GetType(Form1)), Form).Show()Or for better readability, the same code split up:
Code:
Dim FormToOpen As Type
FormToOpen = GetType(Form1)
Dim frm As Form = CType(Activator.CreateInstance(FormToOpen), Form)
frm.Show()
Create A Program In The Form Type?
Jul 3, 2009im supposed to create a program in the form type. its supposed to ask the user for a number so i created a textbox for the entry for the number in the form and a button to execute the program. then the program prints a number of "$$$$$" dollar signs as the entered number. furthermore, only upto 5 "$$$$$" sings should be in a row. oh and i have to use the for-loop for this. i used to be do this when i did qbasic but i have completely forgotten the codes and syntax, etc.
View 11 RepliesHow To Test The Type Of A Form Control
Jul 2, 2011I'm writing a program in which I want to list the values of some of the properties on every control on every form in the application. I can do this for simple controls like Buttons and Labels, but am having a problem when it comes to a complex control like a ListBox. I know how to extract the data when I laboriously code each ListBox individually. The problem is how to do it when it's a generic object buried inside two loops
View 7 RepliesLogin Type Windows Form Using SQL?
Feb 15, 2012What I'm trying to do is have a login type windows form to take a user name and password then compare these with data in the db then open an admin type form. I've been trying to get this to work for a few days now with no luck, about 90% of the code below is a peice together from various forums trying to get it to work. I no longer get an error 26 connection cant be made or what may have you, but now I get "Login failed for user ''.", not quite should what this means or how to go about it.
Private Sub LoginB_Click(sender As System.Object, e As System.EventArgs) Handles LoginB.Click
Try
Dim con As New SqlConnection("Data Source=.SQLEXPRESS;Database=C: cdb cdb.sdf;")
Dim cmd As New SqlCommand("SELECT Username, Password FROM(Users) WHERE (Username = '" & UserTXT.Text & "') AND (Password = '" & PassTXT.Text & "')", con)
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DB has no user/pass needed to open... I think, I didn't set one and the whole app doesn't use one and loads binded data within another form without any problem whatsoever?
Select All Type Of Specified Control In A Form?
Jul 24, 2009All my controls for getting data from user are in TableLayoutPanels and GroupBoxes inside TableLayoutPanel, I want to set default selected index of entire CoboBoxes to 0 in all TableLayoutPanelsand and GroupBoxes inside TableLayoutPanel. [code]...
View 23 RepliesType <Form>.<DatasetName> Is Not Defined
Mar 19, 2012I am getting the following error (in the forms designer code) when generating a dataset from right clicking on a sql data adapter and clicking generate dataset.
The form name is HLT and the dataset name dsSecure
Type 'HLT.dsSecure' is not defined HLT.Designer.vb 74
Type 'HLT.dsSecure' is not defined HLT.Designer.vb 548
Can't Start WinForms Project Because Form Is A Type
Sep 27, 2011I have a very small VS2008 Winforms project that will not start.When I attempt to start debugging the project, I get the message:'<form>' is a type in '<project>' and cannot be used in an expression.From the file .Designer.vb.The problem is that is indeed a form. If I create a new WinForm and set the startup object to the new form, I get the same message.When I attempt to check the "Enable application framework" checkbox in the Project properties, I get the message "Startup object must be a form when 'Enable application framework' is checked.I've tried creating a new project and moving all the code and designer objects to a new form file in the new project, and same result.Other projects on the same computer run fine.
View 1 RepliesForm With Menu Strip - Type Not Defined
Feb 28, 2009If I have setup a simple form named Fmain, in this form I have created a menu strip, this menustrip has a item showing a new for called Frfxcom. In this Frfxcom form I placed a textbox and used its databinding property for connecting to a local database pointing to a certain column in the database named " ip". The database wizard started and inserted some code, at that moment the errors "type not defined" showed up. Here is the automatic generated code:
<Global.Microsoft.VisualBasic.CompilerServices.DesignerGenerated()> _
Partial Class Frfxcom
Inherits System.Windows.Forms.Form
'Form overrides dispose to clean up the component list.
<System.Diagnostics.DebuggerNonUserCode()> _
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Forms :: Type In An Integer Value Into A Textbox And Use It In First Form
Dec 14, 2009I have a question regarding using a TextBox in second form within the same project. Currently I am using two forms. From the main form you can click a button which opens the second form. There, I want to type in an integer value into a textbox and use it for the code in my first form. Here's my
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Have A Command Prompt Type Interface On Form?
Dec 27, 2010I would like to have a command prompt type interface on my form. The only thing I am aware of is a textbox, but there are no facilities to have commands and output scroll without keeping the entire history in a variable. That would be an ever increasing variable, which is ridiculous. Is there an alternate way to use a textbox as a command prompt, or is there something else I can do. Another note, is the use of an array. I know I can increase an array with commands, but this is no good either, because some responses in the box need to be paragraphs in length, so even a separate array for command and output is too cumbersome.
View 6 RepliesUse Property Grid In A Form To Edit Any Type?
Jul 22, 2009I have an App where I'd like to be able to edit any type (font, colour, point etc.) at run time and use any of the .Net default type editors. (e.g., font/ colour picker).
Rather than re-invent the wheel, I decided to use the property grid control.
If I pass an object of, say font, to the grid, it lists all the fields separately, with no option to open the font picker.[code]...
VS 2008 Casting Data-type To Same Data-type?
Dec 5, 2009I have one question. i have seen some codes like:
Req = CType(System.Net.HttpWebRequest.Create("url"), Net.HttpWebRequest)
Is it really necessary to cast the same type, or is there a difference when its not casted.
Check An Array Field Is Empty When Type = Form
Jun 4, 2011I have an array set up to receive the names of forms when they open. The form name is sent as a Form not a String therefore when I run my code I cannot check for whether the field is empty in the normal way (ie. array(1) = "") as the "" are only usable with strings!
Dim Forms(24) As Form
Dim i As Integer
Dim Free As Integer = -1
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I only need a solution to do the same as array(1)="" but for windows forms.
Control 'ValidationSummary1' Of Type 'ValidationSummary' Must Be Placed Inside A Form Tag
Mar 5, 2009Am faced with the above problem which I have failed to understand. the details of the error are given below.
Code:Control 'ValidationSummary1' of type 'ValidationSummary' must be placed inside a form tag with runat=server. Description: An unhandled exception occurred during the execution of the current web request. review the stack trace for more information about the error and where it originated in the code.
Exception Details: System.Web.HttpException: Control 'ValidationSummary1' of type 'ValidationSummary' must be placed inside a form tag with runat=server.
Source Error:
An unhandled exception was generated during the execution of the current web request. Information regarding the origin and location of the exception can be identified using the exception stack trace below.
Stack Trace:
[HttpException (0x80004005): Control 'ValidationSummary1' of type 'ValidationSummary' must be placed inside a form tag with runat=server.] System.Web.UI.Page.VerifyRenderingInServerForm(Control control)
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Make Console Type In A Command And Hit Enter By Itself With Form
Mar 6, 2009Note: I'm using VB express 2008 I would mostly like to learn about the console application. Like how to make it type in a command and hit enter by itself. The project I'm working on is a booter for my iPod (Long story) I would like to be able to- 1- Either click a button on a form and have the console pop up and input
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