What Data Type Will Allow The User To Input 0 And Allow The Mathematical Functions To Work Properly
Mar 29, 2011
I am currently using double data types. The problem I am encountering is that sometimes the user will have to input a value of 0 in the required text box and this creates an error. My question is what data type will allow the user to input 0 and allow the mathematical functions to work properly. Decimals maybe?
I am making a simple calculator that will evaluate functions I have a entry box and the user types in simple equations i.e. 1+4*3/5=? how would i make this evaluate the string?
i want to make a program in which the user can input a mathematical function so the program can then work with it. So the user would input something like x^4+x+2 and then an x and the program would calculate f(x). What i don't know is how to let the user input the function.
I need something tje user can type in data to such a parts QTY cost etc. There are no predefined parts list so the user can enter any part name/Number and there is no limit to amount of parts that can be entered.
Does anyone have any idea what might be useful. It was thinks of a listview bu i can't see that you can type into that. I cant use comboboxs because there are no predefined list and i know there is some way to generate text at runtime (i think) but i don't know how to do it and i would prefer a clearer approach.
How do I determin if a user has given me what I am asking for in terms of data type.
Example if my prompt to the user say "Give me a number of double data type"
How can I tell that the user entered a double xx.yy?
Or if I am testing for integers and I get user input ABC.GH?
I know about CDbl and CInt and CStr but these don't work unless data is provided. Also how do you test if the conversion took place? Also how do you differencate between 12.00 being integer?
iam currently working on my uni project and i have encountered a problem with valadation section.My system displays a message telling the user to input any fields that they have missed out on, listing the name of the field. However as these IF functions are in order the user must input the data in the order of how it is in the code. for example if the "consweight" is inputed and the calculate button is pressed, it thinks that all valadation above it has occured, when those fields are still empty.
In this application I need to allow users to enter a month as integer (1-12) then use integer tryparse to validate that input, that seems to be the easy part. I need two create two functions, one that returns the name of the month and the other returns the number of days in that month. The arrays are supposed to be defined and initialized within the function so that the main program can take the user input and call the two functions, then return the appropriate values as output to labels. I am not sure how to declare the arrays in their appropriate functions and then how to call those functions to retrieve the right value from the function.
I'm familiar with Visual C# and the try/catch for that but I cannot seem to figure out how to do the same thing in VB. Basically I can't figure out how to get the try/catch to work with text boxes and input from the user and whatnot.I've tried setting the textbox.text property = "" but that has no use, I've been trying to find something on Google about it but I cannot seem to find a single thing about textbox try/catch statements. Is it possible to do it with text boxes?
I want to be able to have the user type in a function, say ,x^2 + 1, and have the computer store this such that it can be recalled and plug in a given value for x. For example, say they type in x+4, the program will then (in a bunch of different text boxes) return the value of x+4 when x = 1, x = 2, and so on up to x = 10. But how can I get it so that it will store x+4, be able to recall it and replace x with it's given value
Option Strict On Public Class Form1 Private Sub btnDistance_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnDistance.Click 'The btnEnterSpeed click event accepts and displays up to ten speeds from the user'and then calculates and displays average speed
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I cannot figure out how to incorporate the number of days into the input box then get it to loop and count the number of times the User inputs in the number of days. Then I have to incorporate it into the equation to get the total distance D = MPH * Hours. What I have right now wil not count up the number of days and locks up after I input one number and will not add anything to the listbox. Because I also have to make sure that they cant add nonnumaric values and the number of hours per day cannot exceed 20. I have put things in and taken them out but it has been 2 days and I am lost now
I have a text box labled QTY, which feeds the QTY column on a datatable. the table then is ran through a function that takes the data and converts it to a string which my production machine can read. My problem is this, and its probably really simple (these problems usually are) how to i force the user to use a specific type of input on the txtbox so they would have to put the QTY in the format of 01 02 03 etc etc, i have it set to default to 00 but i want to force the user to haver to input 2 chars.
I am creating a gridview and need to gather the data from various functions that return a type of IEnumerable. I've created gridviews using a dataset as a datasource, but how does one use multiple data sources(of IEnumerable) to populate one gridview? Like how do you combine all that into one dataset?
how to do different things and right now I'm building a simple program to where the user inputs thier First and last name into two different text boxes and when they click on a button it tells them what they have entered.I'm trying to make sure that they have entered letters only in each text box and if they don't I want it to display a message box that says they need to enter letters only.The problem I am having is if they enter a number in both text boxes then that is the only way that it will display the error message box. Here is my code for the data validation for the user input.[code]
I'm just trying to create a graph where the user can input data into textboxes and then plot the data. I am attempting to use Zedgraph, but open to other suggestions. The program below creates a plot, but it won't update when the textboxes are updated.
Imports ZedGraph Public Class Form1 Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
How do you validate input when you are dealing with doubles. I have successfully gotten the message box to pop up when the user enters a number in a text field, but what if I have a text box that requests a number from the user and they enter text? This is the code, the even for btnDisplayFull works fine, but not btnDisplayRqst: [code]
I have used following code to create and write the user input data to XML through Dataset. Hope it can be understood by looking the following code:[code]But the above code is not working. it is not writing the value in XML file.
I want to create a page in asp.net website . it has to have one text box . the user enter the productcode in the textbox and click on search . when the user click search i want to display all the information about that product from product table.
I have two pages the first one will receive all data that are required from the user such as username e.mail and then the same page will do the calculation but when clicking on result button two things should happen: 1-the result and all user inputs should be sent to the second page 2- the same information should be sent to the user email as the e.mail messege
I'm trying to make a program where user can input data from a textbox into an array and when the user hit the enter key, it compare it to a data grab from a text file. Here is my code so far:
Private Sub TextBox_KeyDown(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles TextBox.TextChanged Dim input As String
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I got the part where the program can graph data from text file and put it into an array called "varia3". The part I could not get is allowing user to enter data into the textbox. When I run the program, the sec I try to enter a letter or number into the textbox the program ended.
So I'm developing a Windows Forms Application in Visual Basic 2010. The user searches for data and fetches results, updates fields and some other CRUD operations. I want to provide a user input validation. Usual stuff i.e. some fields need to be always numbers>0, others need to be non-empty in order to avoid Null access on some objects and others just need to be some fixed strings.
It's been a good few years since I dabbled in VB and I'm very very rusty so any help would be great! What I'm looking to do is search an access database with user input and display the relevant record.I have a single table set up in an access database called school_info with the following fields and data:
I've linked the database to my new project, connected the database and added the 4 fields to my form. When I run it, the data shows in the boxes fine.The Tres and DfE fields are show in text boxes on the VB form, and the school and Type are show in labels. What I really want to do is be able to manually type in either a Tres or DfE number into the relevant text field and have the other labels auto populate with the relevant data that's stored in the database table.
So far i have a really basic form application that allows a user to enter some information and does a small calculation, displaying all of the information gathered on the final form.
Im looking to try to save this information but have no idea where to start,im trying to just take whatever is in my text field and put it in a table row. I created a one table database in Access and linked it to the form with a button to try and save it.
I thought it would be as simple as tablename.rowname = textbox.text or something but apparently not and all ive ended up with so far is this:
Private Sub btnSave_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnSave.Click Me.Validate() Me.TblCustomerBindingSource.EndEdit() Me.TblCustomertableadaptor.Update(Me.DatabaseDataSet.tblCustomer) End Sub
I dont even think im close, ive just been fiddling with the predefined code in Visual Studio, trying import ect but the button just doesnt seem to do anything.
i have a access database with two tables, one for customer and one for booking.
I then have a form application i made in VS 2008 which lets a user enter details such as their name phone number ect into text boxes.
All of the information the person enters thoughout the program is shown via labels at the end, all on one form.
Would it be possible to then have a button that when clicked saves all of this information into the access tables into the correct columns, im sure it must be possible i just don't really know where to start.
I've worked out how to display charts in VB 2010 Express, but now I'm needing the user to input data into a spreadsheet/table that will be used within the program. I know that table is no longer available and neither is the OWC11 set. Is my remaining option then to use DataGridView? I know it is SQL based and I don't have much experience there yet, but I didn't want to commit to it if there is another method that would work just as well. The values that are put in by the user does not need to be preserved.
I'm developing a windows forms application using VB.NET. I'm currently working on DataReport (by Microsoft, not Crystal). Everything works fine when using DataSet as DataSource. But I have a question on how am I going to put data to my DataReport from a user input? Preferably when the user is on the act of printing(clicking the print button in the ReportViewer), a Form will pop-up and ask him for input. That input I'm talking about is random names of people, and we don't have to track their names so there's no reason to put it on the database.
I created a sql stored procedure that will insert data for me depending on user input. Now I would like to know usually I would do something of this nature
Dim con As New SqlConnection(connectionString) Dim cmd As New SqlCommand("usp_userinput", con) 'references connectionstring and calls store procedure cmd.CommandType = Data.CommandType.StoredProcedure 'sets default to be storeprocedure lblMessage.Text = String.Empty With cmd.Parameters If (Session("UserInitials")) IsNot Nothing Then .AddWithValue("@UserInitials", Session("UserInitials").ToString()) End If End With
That is just an example how i usually approach calling the stored procedure in vb. However for this particular form I am going to have 50 or 60 textboxes which each one would require a session state variable.Seems a little tedious to have to create a session state variable for each textbox on the form.
My VB app will not work properly on a Windows 7 64 bit PC.When I launched it on the Win7 PC it will open up OK but when I open a crystal report, the form page comes up ok but the report is missing.Then I get a pop up window asking me for a user name an PW: