Validating Empty Text Box In Winforms .NET 4.0?
Jun 21, 2012
I am just adding validation into a new winform. I am using the validating and validated events, in conjunction with an error provider control.No problem with first validation (ie. if user enters more than 12 characters). Error is set in validating event, and error stays until user enters 12 or less characters. Validated event is then entered and error is reset to empty string.
However, there is a problem with the 2nd validation on same text box. The code checks for zero length in text box.. and sets error with provider. Watching in the debugger, this code is indeed invoked, and error is set ok. Then something weird happens, the validated event is (unexpectedly) fired, and the code there promptly resets the error. Why is the validated event fired when there is already an error set ? This seems like a .NET bug. Can anyone suggest another way of doing this, or say what I am doing wrong ?
[Code]...
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Jun 21, 2012
HStrange Issue Validating Empty Text Box in Winforms
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May 19, 2011
I have a problem in that I have five text boxes pertaining to a customer/client, where there is a txtbox for each: Name; Address; City: State; Zipcode. Of course all the txtboxes are "" at initialization. I also have 2 combo boxes and a 2D array for prices which I have finally been able to understand the array logic. I have also been able to do my necessary calculations for.
My problem. The customer information is first to be validated as all being strings and not empty. The combo boxes I was able to get to tie to my 2 dimentional array and get good output and calculations for a finished product. I am just having problems with the error messages. Also I don't want summary totals unless the data is valid. In other words, the user must enter a complete address and make decisions about the two combo boxes, both of which are needed to use the price array. I will change the comboBoxes to represent dress sizes,"S" "M" "L" and "XL" and the other combobox to describe colorRedSatin or colorBlackBroadcloth with a two dollar difference in price between them. 'That would be similar enough to the problem I need to solve.
Basically I do not want any numbers to appear for price of the dress or addons to the dress unless all validation is complete. I do understand how the radio objects work for discounts and check boxes for accumulating accessories. The program should not give any totals untill the user has input all customer information and made decisions about input from combo boxes and selected calculate from menu. Right now it calculates and puts zeros in when choices are not made from the combo boxes by the user. It will include correct amounts for radio buttons and checkboxes if anything is entered. I need error messages for customer inputs and combo box inputs (if not selected from list of option in drop down for choices) (basically if nothing was put in a text box, the text box is empty. Of course the problem is the user must enter something in all 5 textboxes and not get multiple error messages in rapid succession to fix. We can't always count on our users putting in good data.. When I tried a Do While False with ORs I was getting endless looping. I could not get it to work because it will never execute because the control never passes back to the user.
I don't want to list a series of If/Thens becauser the user will see about 7 messages, where he/she only needs to be fed one at the time. I hope someone can give me some direction. I just need guidance on how to validate the text boxes and combo boxes. The code is analyzed with a "Calculate" on the menustrip. I would like for the calculation not to calculate and put outputs into the summery text boxes unless all textboxes are filled and combo boxes are valid for all the customer information and combo box choices for my two combo boxes describing what is needed for the order to calculate. There are also the radiobuttons and checkboxes, DIMs, Const, Variables, but not having problems with that part I have my indexing problems on the combo boxes worked out also, so I am not concerned about those now except for getting the error messages when I should. I hope that I have described my issues fully. I am using visual studio 8 with Windows 7
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May 24, 2011
I have an ASP.Net 2.0 textbox which I need to be validated as having some content, but where whitespace alone is valid input. A required field validator seems to reject a pure whitespace input as invalid. A regular expression validator won't fire at all on empty content. Is there a simpler way round this than using a custom validator control?
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Sep 11, 2009
In WinForms I could handle the Validated event to do something after the user changed text in a TextBox. Unlike TextChanged, Validated didn't fire for every character change; it only fired when the user was done.Is there anything in WPF I can use to get the same result, an event raised only after the user is done changing the text?
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Jul 8, 2010
In a Windows Form application I have a Form with a UserControl that contains a child control. I have an event handler for the child control's Validating event. On the parent UserControl I call the ValidateChildren() method. But the event handler for the child control's Validating event does not run. The CausesValidation property is set to true on both the parent UserControl and the child control. Is there any reason why the Validating event handler would not run?
The child control is a custom control derived from Panel. It contains two RadioButton controls, both of which have their CausesValidation property set to true.
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Sep 28, 2011
what is the most robust method for adding a empty row (to select "nothing") to a ListBox?
Dim List = Enumerable.Repeat(New TABLE With {.Text = "", .ID = -1}, 1).AsQueryable().Union(From t In mainctx.TABLEs)
ddlMangelKategorie.DisplayMember = "Text"
ddlMangelKategorie.ValueMember = "ID"
ddlMangelKategorie.DataSource = List.ToList
But this has some drawbacks:wordy must explicit write the Type (TABLE in this case), so i cant wrap this in a function have not found an solution, which works with anonymous types I.e. if I add a From t In mainctx.TABLEs Select Text=col1, id=col2 to the query, this method does not work anymore.
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Feb 23, 2011
I have a form that has a text box that I want to only allow users to enter a date and then a MessageBox.Show stating that their data was submitted when they press a submit button. I know that you can do this with a regular expression validation but I have no idea how to do this in Visual Basic. Can anyone offer how to do that?
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May 5, 2011
I have two text boxes on my form (Text Entries) How do I code either the button or the text boxes to ensure entries are made in them Regards
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May 18, 2010
-When adding a consignment, the system should generate the consignment number automatically in the format XY12-xAB, where x is a number that increases by 1 for each consignment AB is the Shipment Type (EA, SA or SF) and XY12 is the Office ID.I know how to validate it to be XY(digit)(digit) by using regular expression.
If Not Regex.IsMatch(txtShipConsignmentNumber.Text, "(?s)^(XY)d{2}$") Then
MsgBox("Please enter a valid Shipment Consignment Number e.g XY12")
txtShipConsignmentNumber.Select()
But not sure how to implement the other stuff required.
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Oct 10, 2009
how do I validate that only letters and spaces have been entered into a text box.
Here is a sample of my
Private Sub btnWrite_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnWrite.Click, mnuWrite.Click
If Not txtName.Text Like "[a-z][A-Z]" Then
MessageBox.Show("Please enter your name using letters and spaces", "Error")
txtName.SelectAll()
[code].....
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May 5, 2011
I am having a problem with validating multiple text boxes in using VB.net. I have all boxes validated to display errors if the calculate button is click and the boxes are blank and I have each individual text box to display an error message if the appropriate requirements (values) are not entered. The issue I am having, I don't want these errors to pop up when a user clicks the clear button to re-enter new values,in which this occurs on each box. Below is the code I have for validating each textbox. If a user clicks the clear button (in which clears all text boxes) I still have my errors displayed to them in which I don't want
Private Sub txtLoanAmount_TextChanged(sender As System.Object, e As System.EventArgs) Handles txtLoanAmount.TextChanged
If IsNumeric(Me.txtLoanAmount.Text) Then
[Code].....
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Sep 8, 2009
I'm working on a program to calculate Exp left until a title is available in game. I'm trying to validate that the user enters only numbers into the text box. Should s/he enter a letter I want my message box to show and then select the text that was incorrectly entered. My problem is in when the backspace key is hit it again shows the message. I believe it's in the TextChanged event but i'm not certain..
'Handles txtXP Box & Validates user input
'Converts over to a Double Number
'Provides Error Correction if anything other than #'s Used.
[code].....
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Apr 3, 2011
I have textbox on my form, the details are below:
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Aug 31, 2009
I'm searching an MS Access database on a text box entry but I want to validate it to make sure that its not empty and that it is equal to a value in the table, if it meets these requirements it displays the table contents
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Jan 13, 2010
I have an application that has more than 20 text boxes used as inputs(numeric) ( in a form with multiple tabs), and from these numeric inputs I calculate many parameters and display them in other text boxes.The question is how can I trigger an event that will run the calculation procedures each time any of the text boxes numeric values change?( with out having to make procedure for each text box validated eventIs there some thing like a common validation event for any entry in any text box?
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May 9, 2012
I am writing below code for validating compulsary field account no. in form.User's requirement is set focus back on field when error comes :
If txtAccountNo = "" Then
MessageBox.Show("Account no filed can't be left empty")
txtAccountNo.SetFocus
Exit Sub
End If
It's working properly. But suppose user don't want to fill form and exiting from application.Message box keep on appearing till user enters account no.
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Dec 30, 2011
I have a normal textbox which multiline property is set to true and now I need the text written in the textbox should have a large font size.So is it possible with the normal textbox.[code]...
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Sep 18, 2009
I have a mask of : 00/00/0000
I need to check if the masked text box is empty,I tried MaskedTextBox1.Text
it returns --/--/--
How can I check whether the user has entered a value to the maskedTextBox or not?
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Jan 24, 2009
I am using save file dialogue box and i am saving the contents of richtextbox which is in the form. So i used the coding below. It only creating the empty file but not the text which i typed in the richtextbox.
Private Sub Button1_Click_1(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
[Code]...
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Nov 26, 2010
I have written a program which read a file and convert it into my required format, but the problem is at the end there are three empty rows (lines) then "End of Report" message is displayed, here is my code. [code]
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Mar 3, 2011
How do I fill a textbox with text if it is empty? I am using VB.NET.
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Aug 5, 2011
How will I check that the dynamic textboxes is empty;
Here's the code:
Imports System.Data
Imports System.Data.SqlClient
Public Class FunctionProcessor
Dim objcmd As New SqlCommand
[code]....
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Feb 29, 2012
how can obtain the number of empty spaces in the text box?
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May 17, 2010
How I can quit the empty default text that appears in a comboBox when it is loaded?
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Aug 26, 2011
what is code i should use if i want to prevent user not to leave empty word in text box after user click save button.Oh ya, i am using visual studio 2005, databse sql 2005 .Here is my code
Private Sub btnregister_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnregister.Click
If MsgBox(" Are You Confirm", MsgBoxStyle.YesNo) = vbYes Then
[code].....
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Mar 14, 2010
I have a winform project which lists all the files in a specified folder. It allows the user to select a new destination for each file, and when the user has chosen the destinations for all files that he would like to be moved, it moves the files, one by one.My next step is, I need to display a confirm form when the files are being moved, and add each file's name and destination to the confirm form as it is being moved.How can I add more text to the confirm form's controls after I already loaded it (using confirm.showdialog() from my other form, without any user interaction? I imagine that I need to do it from the original form, because it needs to display each one when it starts to move that file?
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Aug 4, 2009
I have a ListView with 3 columns, how do I add specified text to the specified column I want? I've looked at the ..Add function, but it doesn't take the column index.
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Aug 10, 2009
I dynamically create buttons on a form and use the button text as ids so that I can pass that to an SQL query to pull saved data about that button when necessary, but I also use an image over buttons that have information saved about them. What I need to know is how do I keep the text on the button from appearing when there is an image assigned to that button? By default vb.net shows both the text and the image and no TextImageRelation values allow for the image to take precedence. I tried changing the text color to transparent, but the outline of the text is still visible through the image. Is there anyway to keep the text value as it is but just show the image on the button?
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Apr 19, 2012
I am trying to prevent the User from proceeding if a specific text box is empty. All of the following lines of code SEEM TO work:
If txtTitle.text = "" Then.....
If txtTitle.Text = Nothing Then.....
If txtTitle.text = Nothing Then.....
(followed by a message box advising of the need for input)
The problem is, if the User enters a space (either accidentally or intentionally) all three of the above recognize the space as a valid entry.
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