I am puzzled by why it does not retrieve the data and keep saying i have a error "InvalidCastException", i am currently doing these in compact framework and is totally new to it, i searched around looking for a way to get data into a listview base on what little i know about java . these are my creation of table and inserting during formload
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I'm trying to retrieve values from a look up table with the selectedRows method. But i'm getting the exception InvalidCast. It says: Conversion from string "Codigo" to type'Integer' is not valid. Well my code is varchar not numeric.
Try
frmMovimientos.codDestino = dgLook.SelectedRows("Codigo").ToString
frmMovimientos.desDestino = dgLook.SelectedRows("Descripcion").ToString
Catch ex As Exception[code]....
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And the following sub routine is load in the Listbox_selectedindexchanged event
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And listitem class
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And subsequently I want to Design the select query by adding the three column i.e. First Name, Middle Name and Last Name in the Listbox and by selecting the list item that will show in text box.
I am using 1 listbox and 4 text box. I want to retrieve data from my database i.e. ms access database into listbox I am firing the select query by using this code on Page Load event and list box selecetedindex change event which is following. [code]...
View 1 RepliesI am making a simple calculator and it's saying InvalidCastException was unhandled when I try to debug it, here's the code, please tell me whats wrong with it: (and yes I have renamed the textboxes to addequals etc...
Public Class Form1
Private Sub WebBrowser1_DocumentCompleted(ByVal sender As System.Object, ByVal e As System.Windows.Forms.WebBrowserDocumentCompletedEventArgs)
End Sub
[code].....
I have some trouble in SMS gateway project using VB.Net (VS 2010)while programme was running, I found error "InvalidCastException was Unhandled", then my programme cannot continue. below I copy the code of the programme :
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Option Explicit On
Public Class MessageReceiver
Private TPMessageTime As String
[code]....
I am trying to catch the System.InvalidCastException error. If I put a number into the calculator the program runs ok. If the calculate button is pressed with nothing in the text boxes I get the casting error Conversion from string "" to type 'Decimal' is not valid. I understand why I am getting the error. I don't know what to do about it. I want the program to dump null data and go back to waiting for input from the user.
Private Sub btnCalculate_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnCalculate.Click
Dim FedTaxRate = 0.13 ' constants for taxes and work week
[code].....
I use code such as this to clear out the values in several text boxes: Private Sub RibbonButtonInsert_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles RibbonButtonInsert.Click
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Because the date picker control did not clear out like the other controls did, I tried:
DatePickerDateOfBirth.Value = ""
but it does not clear out. Instead, I get an "InvalidCastException". show me what coding I need to properly clear out the value in this data picker?
I have used the Gridview_PageIndexChanging event in asp.net.i have used the code like this:
gridFileDetails.PageIndex = e.NewPageIndex
During the run time when i clicked the next page,it generates an error:
An exception of type 'System.InvalidCastException' occurred in FFK.DLL but was not handled in user
code
Additional information: Unable to cast
object of type
'System.Web.UI.WebControls.ContentPlaceHolder'
to type
'System.Web.UI.WebControls.GridViewRow'.
in the RowCommand event,I have used the following RowCommand event:
Protected Sub gridFileDetails_RowCommand(ByVal sender As Object, ByVal e As System.Web.UI.WebControls.GridViewCommandEventArgs) Handles gridFileDetails.RowCommand
Dim row As GridViewRow = CType(CType(e.CommandSource, Control).NamingContainer, GridViewRow)
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Error is Simple Application -- Error Type (A first chance exception of type 'System.InvalidCastException' occurred in Microsoft.VisualBasic.dll)
View 3 RepliesI'm implementing following code in VS2010:
If xl.cells(1, contacolonna).Borders(Excel.XlBordersIndex.xlEdgeRight).LineStyle <> Excel.XlLineStyle.xlContinuous Then
MsgBox("hello")
End If
or following
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but in both cases VS returns following error:"InvalidCastException was unhandled Overload resolution failed because no Public '=' can be called with these arguments:'Public Shared Operator =(a As String, b As String) As Boolean':Argument matching parameter 'a' cannot convert from '__ComObject' to 'String'. "
Im trying to improve some apps ive written, the first is a console app... Im trying to get it so that i wont get an invalidcastexception if the user inputs a string, when the variable is type "Double"
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I have this issue with casting....is there anyway i could pass an integer into a label...this is what i have done so far but i am getting this error "A first chance exception of type 'System.InvalidCastException' occurred in Microsoft.VisualBasic.dll"
Dim firstNumber As Integer
Dim secondNumber As Integer
Dim solution As Integer
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I have just upgraded to Microsoft Visual Basis 2010 Express (Running on Vista and Microsoft Office Excel 2007). The last time I used VB was about 5 years ago and was v5.0 I am trying to do the very simple action of opening a spreadsheet using VB and reading in cell values into two text boxes (I am using an example posted on the web to ensure my approach is correct). The run fails at the point:
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In my project I'm trying to get the caption property of serial ports available on computer. But when I run this code below I get "A first chance exception of type 'System.InvalidCastException' occurred in Microsoft.VisualBasic.dll" exception. I tried putting "Option Strict On" and then I'm getting build error saying it disallows Late binding.
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EDIT: Solved (see comments) I have a For loop inside a sub, and right below it I have a MessageBox function. Everything compiles correctly, however for some reason, if the loop executes and exits successfully, anything outside and below the For doesn't get executed.
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it displays only 10 items in the ListBox afterwards. I've searched everywhere, but I did not find anything related to such an issue. I'm kinda puzzled, anyone got a clue of what's going on? EDIT: Forgot to specify, the sub is actually a TextBox.TextChanged event
So my teacher gave us this assignment that I'm having trouble understanding why she wants us to write outside of the button Private Sub.1. Write the code for the Calculate Total and Grand Total button a. Declare a variable to accumulate the individual totals outside the sub procedures b. Calculate the total by multiplying the selected number of atendees by the selected cost, and display this total in the label next to Total c. Calculate the grand total by adding the total calculated in step 3.b to the grand total variable. Display the grand total next to Grand Total I'm don't understand why she says 1a. I feel like you can just write all the variables in the same Sub on the calculate button.
View 8 RepliesHave to develop an application that will let me choose between cell phone plans, individual and family plans i have the forms and all choices done,. new forms open and old ones hide to keep it clean. i think i got all the variables declared, and got no debugging errors, but when i select the options, it always gives me the following:
1. adds one more phone than selected
2. only shows phone subtotal, tax and total
3. prices for options and monthly fees never show
Here is my code for all 3 forms
Public Class frmMain
Private Sub btnExit_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnExit.Click
End
End Sub
[code]....
I am developing an ASPX VB.NET file. My assignment is to convert an integer representing week of the year into that end date. For example, if user selects Week 4 for 2011, I want to get date = 1/22/11. How do I do this in VB.NET?
View 2 RepliesI'm supposed to change the keyboard language to Farsi(Persian) by using API functions while the program is running( It's a plain form with a text box). I'm already late for the due date.
View 1 RepliesI have two drop down boxes in my program. When you select an item from the first drop down, it populates select-able items in the second. When I select something in the second and then change the selection in the first one, the values remain in the second. How do I "reset" the second drop down when the first is changed?
View 1 Repliesdisplaying the first 10 Fibonacci numbers. My code displays the following result: 1, 2, 3, 5, 8, 13, 21, 34, 55 and I need it to also display the first two Febonacci numbers (0 and 1). How would I do that?
Public Class Form1
Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
Dim a As Integer = 0
[code]....
If i have a class called A and a class called B, if B inherits A that means A is the super class and B is the subclass. I have been asked to describe why class A is not an abstract class but as i see it class A is an abstract class A, as it has been created for Class B to use in the future, is it something to do with Class B not being able to access the fields in Class A as although they are private by default?
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I am trying to unit test for data being input into a textbox (txtPrice). If it is not numeric, it throws a messagebox stating that the input must be numeric. However, when I unit test, I can't figure out why my test fires the message box twice.THis is my (simple) unit test:
Public Sub txtBoxes_LeaveTest()
Dim target As frmEstimate_Accessor = New frmEstimate_Accessor ' TODO: Initialize to an appropriate value
Dim sender As Object = Nothing ' TODO: Initialize to an appropriate value[code].....
My understanding is that for unit testing, you declare the sender, and (in this case) set the sender to some value that will trip the message box. 112L should do this on the leave event. I then write my expected, which in this case is 112L, fire the event, and then get the actual out of the text box. I then Assert.AreEqual to ensure the expected and actual are the same.
Working through trace tables and wanted to check to see if my results where correct, I have designed the following code to check each stage of the loop, but the code keeps throwing up an error about casting when i try to run it. I can see when the error comes back that the writeline is holding info but what have i done wrong.
Module Module1
Sub Main()
Dim aWord As String
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I have three tables in SQL server which I would like to show and access on a form. Table 1 contains account data, address, contact details etc. Table two contains data attached to a Person, tel no , Mobile no, Email etc. Table three contains details on what awards the person holds, i.e. one person can hold several awards.
Therefore I have a one many relationship between the first two tables and a one many relationship between the second two tables. This is set up in SQL
The first two tables are shown on a form, table 1 via a set of text boxes, table 2 via a datagrid control.
I would like the functionality whereby I could select a row in the datagrid showing the persons name and find the Persons_ID number then use that as a filter to a second datagrid view so that only the selected persons awards show in the datagrid.
For a school project we need to visualise a computer network graph. The number of computers with specific properties are read from an XML file, and then a graph should be created. Ad random computers are added and removed.Is there any open source project or algorithm that could help us visualising this in VB.net? Or would you suggest us to switch to java.
Update: We eventually switched java and used the Jung libraries because this was easier for us to understand and implement.
i want 2 select data from data gridview and want retrive that data into another form in to the textbox ...is it possible ? i 'm doing like this for that
Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.[code...]
I've been taking a class on it this semester and am starting to get very confused and behind. I've been pretty stuck on my hwk assignment for this week and was wondering if anyone could possibly hint at what I'm doing wrong or if I'm just completely way off. The whole rows and columns in arrays seems to be throwing me off now. Also, sorry if this is not the right place to post something like this I was not sure which section this fit under.
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I was given an assignment to "write a program to print only even numbers between 6 and 16 using events", but I don't even know where to begin. The main thing I am having difficulty with understanding in this assignment is how I am supposed to specify that it only print even numbers in the given range of numbers.
Am I going to have to do a Mod2 code for each individual number and have it exclude any with the result of 1? Or is there another piece of code specifically designed for such an occassion? Perhaps there is some type of equation I can have the program read in terms of a variable, which holds the values of 6, 8, 10, 12, 14, and 16? I am just genuinely confused on how this is supposed to be programmed.