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.
View 3 RepliesI currently have this line of code which has been working for the past 6 months:
If IsNumeric(txtProductID.Text) Then
...do stuff
Else
Dim msg As String = "Error!"
End If
All of the sudden, no matter what kind of entry is put in txtProductID (including plain numbers), it fails! Is there reason for me to be going crazy over this?
What is the C# equivalent function of IsNumeric() in VB.. If possible include an example.
View 4 RepliesI have a function in VB.NET that loops through values and attempts to convert it to a decimal if IsNumeric is True,
Dim Value As String
If IsNumeric(Value) = True Then
Rate = CType(Value, Decimal) <--- bombing here
End If
I've found that when the function receives the value 603E43 IsNumeric evaluates to True for some reason and then bombs on the conversion. Why would IsNumeric be true in this case?
I want to change the IsNumeric to string in the code below but IsString gives an error how can i go round it Private Sub txtprojtypenw_Validating(ByVal sender As Object, ByVal e As
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I have VS2005 and I'm trying to use a function like isNumeric, except it accepts an array of strings.
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I keep getting errors, anybody know why? Might just be a stupid mistake, haha its been a long day today.
Public Class Form1
Private Sub Button1cmdRun_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1cmdRun.Click
Dim hour As Integer
Dim minute As Integer
Dim second As Integer
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Whenever I run the program and I enter text into the label the program crashes. When I type in a negative number the message box works. A number like -45 worked and a message show appeared, whilst a string like 'bob made the program crashed.
When was isnumeric considered legacy code? I guess all that i have learned from my college class last semister is legacy.
View 4 RepliesI 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
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I'm working with visual studio 2008 developing software for windows CE 6.0, compact framework.I'm having this "strange?" trouble with isNumeric method. Is there another better way to do this job? Why is getting me an exception? (two in facts...both of type FormatException)
dim tmpStr as object = "Hello"
if isNumeric(tmpStr) then // EXCEPTIONs on this line
// It's a number
else
// it's a string
end if
Following a recomendation from an expert, I removed the Microsoft.VisualBasic Reference from my project in order to "clean" the code and use only .NET. Almost anything I have been able to fix except I cant find the equivalent of IsNumeric or IsDate functions.
View 13 RepliesI have some customized string formats of double values. I need to convert these strings to double values at some point (Note that these strings may contain error messages other than numbers). So I first check if these strings are numbers, and if yes, then convert them to double. Isnumeric works for my first customized string format. But I found that is numeric cannot recognize percentage strings. I wonder why isnumeric understands () but cannot understand %. And what is the better way to convert "(100.00)" and "50%" to doubles other than Cdbl?
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I had a strange error in a VB6 app this morning and it all stems from the fact that IsNumeric is not working as I expected. To me this seems like a bug.
This code displays 4.15877E+62 in a message box:
Dim strMessage As String
strMessage = "0415877D57"
If IsNumeric(strMessage) Then
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I am guessing that the runtime engine is incorrectly thinking that the D is in fact an E? I think this is a bug though as the exact same code in VB.NET outputs not numeric Is this a known issue with IsNumeric?
Private Sub Bearing_Textbox_KeyDown(ByVal sender As Object, ByVal e As System.Windows.Forms.KeyEventArgs) Handles Bearing_Textbox.KeyDown
If e.KeyCode = Keys.Enter Then
e.SuppressKeyPress = True
Call Plot()
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Which is used to plot bearings. The user inputs a bearing of 0-360 degrees. It works fine if a user say types in "abc" or "/" i.e. anything that isn't numeric. But if a user types in "90/" then it allows it. When the bearing is plotted the keypress is surpressed so the user cant then go back an edit. Is there a quick way to amend the code to allow for this?
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)
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>
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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.");
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 ?
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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:
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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"
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:
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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.
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)
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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.
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.
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?
View 4 RepliesVb is not my language of choice , but I have to do this for school and I'm not having a very easy time with VB's documentation.I'm just creating a very simple console application that accepts user input: degrees in Celsius, and converts it into Fahrenheit. I want to make sure that if the user just hits enter without entering the degrees in Celsius, then an if else statement will catch and write to enter Celsius again.Here's what I've tried:
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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
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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.
View 14 RepliesHow to deal with a "date bug" that I have encountered in my program. Here is a scenario.
1. My system has a locale of en_US and therefore displays the date as MM/DD/YYYY
2. My program tries to import from a csv file in which it carries out tests on a field to check for a valid date before loading the rest of the data.
3. If the date in the file is in the format DD/MM/YYYY the test fails and therefore the data is not loaded. This is the bug.
I would like code to test for the date string in the csv file that will recognize any date format (locale).
I am trying to write the code for a conference:
1 person costs $695.00
2-4 people costs $545
5-8 people costs $480
8 or more costs $395
If the company has been before they get a 15% discount and no company can have more than 16 people. The program asks that the user enters valid data.?? (error msg boxes)
I am trying to get valid data entered in a Windows Form.I simply used bunch of IF and ElseIF statements to set the conditions.
1. Because the field can only accept letters, I need to filter out characters. Eg: !@#$, stuff like that.
2. I need to apply a loop so that the user is prompted to re-enter the data or to have the error message repeat. Right now the error message display once and that's it.I understand the Do Until Loop but my book shows example only on numbers.
Public Class validDataForm
Private Sub validDataForm_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
End Sub
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