Using Integer.TryParse For Validation An If Statement?
Feb 12, 2012
this is for homework but I have 90% of the project done, I just need to finish the data validation portion of the code.This is what I have for the calculate click event:
Private Sub btnCalculate_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnCalculate.Click
Dim intInputA As Integer
Dim intInputB As Integer
Dim intInputC As Integer
[code]....
My Problem: I am using the Try parse to validate weather the inputA(B)(C) is an integer or not, if it is an integer, i want it to move to the nested if and validate that it is a positive number, and show the error message in the label if it is not. If it is not a number at all i want it to show another message in the label. The problem that I am getting is that even if i put in a letter for the input it does not catch it and it continues on to the select case, which comes out 0.
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Jan 26, 2012
this is for homework but I have 90% of the project done, I just need to finish the data validation portion of the code. This is what I have for the calculate click event:
[Code]...
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Jul 3, 2009
My understanding of the Integer.TryParse() function was that it tried to parse an integer from the passed in string and if the parse failed the result integer would remain as it did before.
I have an integer with a default value of -1 which I would like to remain at -1 if the parse fails. However the Integer.TryParse() function on failing to parse is changing this default value to zero.
Dim defaultValue As Integer = -1
Dim parseSuccess As Boolean = Integer.TryParse("", defaultValue)
Debug.Print("defaultValue {0}", defaultValue)
Debug.Print("parseSuccess {0}", parseSuccess)
[Code]....
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Mar 10, 2009
The code performs correctly when the input is an integer, but when I enter a character, the result is as though I've entered an integer. Can you tell me what's wrong with my TryParse statement?
Private Sub btnCompare_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnCompare.Click
' Declare Local Variables
[CODE]...
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Nov 9, 2009
what should I write to validate that my textbox.text include string only or integer only
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Dec 7, 2011
I have Tried to convert "1" to integer using Tryparse it showed true but when I used it on "1.00" it is showing it as false, why?
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Dec 15, 2011
I want to enforce validation rule in create table statement for a coloumn. im using vb.net as front end and access as back end.
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Mar 27, 2012
I have a function that returns a Datatable. I am passing a list of Integer as an argument. Then I thought tis would work.
Public Function GetEventsByEventType(ByVal EventType As List(Of Integer), ByVal DayInterval As Integer) As DataTable
Using con As New MySqlConnection(strCon)
[Code]...
as you can see. I use string.join to convert the list of integer to something like this. '1,2,3'. Problem is that is read as a string so i get the incorrect results. I need to have where EventType IN(1,2,3).
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Dec 17, 2009
I am trying to check this app. and make sure only numbers are placed into the textbox, but my tryparse isn't working.
Private Sub btnConvertC_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnConvertC.Click
Dim intTemp As Integer 'holds the text input
If Integer.TryParse(txtTemp.Text, intTemp) Then
[code].....
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Dec 11, 2011
I have an array of 5 objects and also 5 textboxes. I am wanting to check to see if the values in the corresponding textbox are valid for the type of object.I have currently hard coded this, I parse out the object type and then use a tryparse statement depending on the object type.
Can I do this automatically? Can I detect the type and use a tryparse statement for that type. Maybe something like:if objectarray(x).tryparse(textbox(x).text, nothing)
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Aug 21, 2009
I have become accustomed to using TryParse for attempting to parse unknown types:
Dim b As Boolean
Dim qVal As Boolean = If(Boolean.TryParse(Request.QueryString("q").Trim(), b), b, False)
or
bool b;
bool qVal = (Boolean.TryParse(Request.QueryString("q").Trim(), out b) ? b : false;
So, just curious if someone knows a better way of doing this other than using a ternary operator.
public static class PrimitiveType
{
/// This function will return a parsed value of the generic type specified.
/// </summary>
[code]....
Just pass in the type you're expecting as the generic and provide a string value to be parsed and a default value in case the string is not parsable. If you provide a class instead of a primitive type it will throw new ArgumentException("Generic type must be a valid Value Type that has a Parse method.");
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Nov 3, 2010
The adultcombobox & childcombobox have value from 1 to 10, and none.I try put it in Do Loop like the code below, but the total price not come up so well, so I think I am having problem with the Do Loop and the Payment method.One more thing, do I need to Tryparse the combobox and use the selectedIndex ?
[Code]...
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Nov 8, 2010
I am in my programming class and we had a small program to make that would check to see if an value that was entered is a integer and convert it to a Roman numeral. I know how to properly do it by putting the TryParse into the If...Then statement. What I am trying to do is to not use an If...Then statement and go just by a Case Selection statement. If it is not possible then that is cool with me, I am just trying to think outside the box. Here is what i have done with it:
[code]....
When you do say "Case 1" it says it needs to be "Case CBool(1)." Using either "Case CBool(1)" or "Case 1 = 1" provides the same result .However the code shows no errors it doesn't do the conversion, it always displays the label's value as "I"
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Oct 11, 2009
On all my assignments I am asked to make sure the data is valid - only numeric, no empty strings. And I keep wondering which is the best to use IsNumeric or TryParse. When I try both on coding they seem to do the same thing, and I don't seem to find my answer online. Any ideas of why to use one over the other.
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Mar 28, 2010
I am creating a program that will convert Celsius to Fahrenheit and visa versa. The program must use a function to return the answer. I'm using a string function that will return either the temperature in Celsius or Fahrenheit or "Please enter a valid temperature" if anything but a number is entered. TryParse is used to check if the input is valid.
When using the TryParse method in the function I am trying to use a parameter to pass the variable that will store the converted data type value [Code] The line " If Double.TryParse(tempTextBox.Text, scale) Then " is supposed to check if the conversion is possible and if it is pass either F or C as a variable to the scale parameter. It seems to verify the conversion all right but it doesn't actually do the conversion. Why isn't doing the conversion? Both F and C remain 0. I can get it to work by using two more TryParse methods (one in each branch of the If else statement in the function), but I'd rather not do this.
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Dec 7, 2010
With a Decimal, I use:
document.Air1 = CDec(IIf(Decimal.TryParse(Air1TextBox.Text, Nothing), Air1TextBox.Text, "0")) to fill the column with there is no value.
I would like to do something similar when the date is blank (preferably with NULL or just plain blank):
document.TestDate1 = CDate(IIf(Date.TryParse(TestDate1TextBox.Text, Nothing), TestDate1TextBox.Text, " - - ")) - of course, this throws an exception.
The table Data Type is date.
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Nov 9, 2009
Is there any way to use the TryParse method to check for letter text input?For example, a user needs to input a name in a text box. Is there anyway to check that input are all letters?
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Oct 21, 2009
How would I code a TryParse to get the input from customer from a textbox named Strands and convert it to a number (this number will always be a whole complete number, cannot be 5.6 or 4 1/2 or whatever) then have that Strand number be muliplied by the selected item in my listbox1. This listbox has an access database bound to it with 2 columns Size and Area, the Size equals the Area and I set the Value to the Area column but set the Size to show up in the list box. and the Strands textbox has to muliply by the Size picked, but by the Area # not the Size #. And the results of that multiplication showing up in another textbox named total.
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Sep 25, 2010
ive got some simple problem i cant understand how to solve.
str(1) is an array and integer(or double, tried both)
a(1) is an array and integer (or double, tried both)
a(1) = a(1) + 1
Label1.Text = str(1) + a
the big part is where i get: operator '+' is not defined for types 'integer' and '1-dimensional array of integer'.why do i get that message and what does it mean? how do i make the code do what i want?
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Aug 11, 2011
I faced an error when upgrading VB6 code to VB.NET. The error occurs at AddressOf WindowProc
AddressOf expression cannot be converted to 'Integer' because 'Integer' is not a delegate type
My declaration for SetWindowLong is:
Declare Function SetWindowLong Lib "user32" Alias "SetWindowLongA"(
ByVal hWnd As Integer,
ByVal nIndex As Integer,[code]....
What is the reason for the error I get?
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Apr 25, 2011
I'm trying to create a linked list of an array of integers. Why is the following implicit conversion required?
When I run the code that contains that conversion, I get the following error.
As a real-time data acquisition user control data (a packet of an array of bytes) arrives every second, is converted into an integer array and inserted into a linked list.
The most recently arrived data is painted as coordinates on a grid at the right of a PictureBox using Graphics.DrawLine (pen,X1,Y1,X2,Y2).
The oldest data (arriving 120 seconds ago) will be drawn at the leftmost portion of the Picturebox.
Why a linked list rather than a list? To display 120 views of time sequence data, the draw routine the most recently inserted node to a node that points to Nothing. How do I limit the length of the linked list to 120 nodes and always ensure that the last node points to Nothing?
Do While Not item Is Nothing
item = item.NextItem
Loop
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Aug 3, 2009
I am a newbie in VB and I got a piece of code which can display the current running program. I need to use that in VB2005 and I got the below error message. Can anyone help how to fix it?[code]
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May 13, 2009
I'm trying to convert a VB6 project to .NET, but I get problems with some callback functions, and the following message comes up: "AddressOf' expression cannot be converted to 'integer' because integer is not a delegate type" I've seen several solutions to similar problems like this, but I am not able to understand this issue with delegates.
After the conversion, the code look like this:
Declare Function vsmsgwSetDataPackageCB Lib "vsmsgwW.dll" (ByVal PACKAGE As Integer, ByRef arg As Integer) As Integer
Dim arginitP As Integer
[Code]...
Which gives the error: Method 'Public Function PackageCB(HisNodeID As Integer, ByRef data() As Byte, ByVal length As Integer, ByRef arg As Integer) As Integer' does not have the same signature as delegate 'Delegate Function DelegatePackageCallback(hwnd As Integer, lparam As Integer) As Integer
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Sep 19, 2011
I have a LINQ2Entity problem, I want to get the value, string, from a database, so I select FProducts.Serial_number, and to end the query, I do .ToDictionary. The problem is, it tells me that it doesn't have sufficient parameters, to convert ToDictionary. So I need something like select FProducts.Serial_number, Nothing). ToDictionary. Also FProducts.Serial_number, 0).ToDictionary doesn't work.
Sub GetStatistics(ByVal ProductNumbers As List(Of String), ByRef Passed As Integer, ByRef FailedProducts As List(Of String))
Passed = 0
FailedProducts = Nothing
[Code]...
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May 9, 2012
this is for a BINGO game final project that I already turned in but this just bugged me that I could not get the sorting figured out. I am trying to get this to sort the random numbers in to columns under the correct letters but I keep getting the error Operator '>=' is not defined for types '1-dimensional array of Integer' and 'Integer' under the line:
[Code]...
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Aug 11, 2011
I am new to EF Linq and I have been struggling with this query for a few days. From reading this forum, I have managed to get this far:
Dim noPic = (From f In myEntities.FriendLists
Where (f.UserID = Profile.ID)
Select f.FriendID).Except(From g In myEntities.GuestLists
Where g.EventID = _id
Select g.FriendID)
[Code]...
I am trying to get everybody from the FriendList who is not already on the GuestList to display in a Repeater control. After reading the forum I was able to append .First() to noPic at the myNoPic declaration and finally get a result but that only gave me the first element. Does anybody have any advice on how to accomplish this?
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Mar 14, 2012
Why doesn't CDate(integer) work where integer has format of YYYYMMDD ?and why won't this stupid site let me submit such a short question when I have nothing else to add except some waffle at the end
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Aug 3, 2010
This is giving me a headache. I have this link query here that grabs an ID
Dim mclassID = From x In db.SchoolClasses Where x.VisitDateID = _visitdateID Select x.ClassID And then later on I have this linq query
ViewData("Staff") = From t In db.Staffs Where t.ClassID = mclassID Select t
I've tried quite a few things but to no avail. I've attempted casting, converting, Is operand, etc.
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May 28, 2009
I'm just writing a bit of code to compare an id of integer with an id of integer? for example:
Dim id As Integer = 1
Dim nullId As Integer? = Nothing
Dim areEqual As Boolean
areEqual = nullId = id
When I try to compile the code I get a compiler error: Option Strict On disallows implicit conversions from 'Boolean?' to 'Boolean'. Whilst it's very simple for me to work around this, I was hoping that someone might be able to explain what's going in the compiler to give this warning.
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Apr 5, 2009
I'm trying to set an Integer value from my.settings.The values comes frpm a listbox, and then inserted to settings (set to specialized.StringCollection)The problem is when i'm trying to get the values and apply them to my function.Error code: Conversion from string "65 & 71" to type 'Integer' is not valid.To me it looks right, but maybe i'm missing something.
Code: Dim test2 As Integer Dim test As System.Windows.Forms.Keysm trigglist As New StringBuilderor Each item As String In
[code].....
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