DataGridView - Convert Nulls To Empty Strings And Display It In The Grid As Empty Strings
May 14, 2009
I have a DataGridView that has some columns with dates. It binds to an in-memory Datatable which gets loaded from an string array of data passed back from the backend Some of the rows returned have nulls for the date columns. Solution 1: If I define the Date column in the DataTable as "string" I can easily convert those nulls to empty strings and display it in the grid as empty strings (desired results). However, if the user clicks on the date column header to sort by date, it doesn't order the rows as you want. You get a purely string sort order. Not acceptable
How can I change the following code to write to the database null instead of empty strings?
Public Sub SetChangeRequest(ByVal referenceLeaseID As Integer, _ ByVal referenceCustomerID As Integer, _ Optional ByVal custUnitNum As Object = Nothing, _
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
The .ColorReportedDate, .ColorTypeKey, .IsColorKeyNull, etc are from my strongly typed dataset row. If .IsColorKeyNull Then .ColorReportedDate = Now() ElseIf cboColorType.SelectedValue <> .ColorTypeKey Then .ColorReportedDate = Now() End If
As the title says I have a form with many databound textboxes. some of these boxes have data in them and some are empty. I need to add them altogether, so far all of the conversion methods I have tried err out when they run into an empty string, except Val, but then Val won't handle the string with a $ in it. I've tried decimal.parse which handles the $ but not the empty string. So I seem to be in circle that I can't get out of.
Say I have a List(Of Tag) with Tag being an object. One member of Tag, Tag.Description, is a string, and I want to make a comma-separated concatenation of the Description members.Is there an easier way to do this than to read the Description members into a List(Of String) and then use the Join function?
How to apply for loop on grid view and to check the empty cell value then show a message... Dim cnt As New DataSet1.LibraryDataTable For i As Integer = 0 To cnt.Rows.Count - 1 For j As Integer = 0 To 5 If GridView1.Rows(i).Cells(j).Text = Nothing Then GoTo e ElseIf GridView1.Rows(i).Cells(j).ID Then GoTo a End If Next Next e: lblmsg.Text = "he is not return a book" a: lblmsg.Text = "he is return all book"
I am working on a UDP Client/Server, and currently i have them sending back and forth strings, which i convert to bytes, and then open the bytes to read. I want to now send an Object instead of those strings, which includes multiple unsigned integers and strings.
I have a list of strings. For each string in that list, I want to prepend another string. I wrote a method to do it, but I was wondering if there was something already in .NET I could use to do this. It seems like something that could be built in, but I was not able to find anything.
Here is the method I wrote:
Private Function PrependToAllInList(ByRef inputList As List(Of String), ByRef prependString As String) As List(Of String) Dim returnList As List(Of String) = New List(Of String) For Each inputString As String In inputList returnList.Add(String.Format("{0}{1}", prependString, inputString))
[code].....
It works, but I would rather use built in functions whenever possible.
I have several problems with rows in a DataGridView. Background information: The DataGridView (DataGridViewCalib) is in one TabPage of a TabControl, some columns of the DataGridView are automatically DataGridViewCheckBoxColumn as the DataSource have some colums which are Boolean. This is a Windows Form written in VB.Net with Visual Studio 2008. The user loads an input data file.
The problems:
1) At first arrival in the TabPage, ShowDataGridViewCalib (code below) is called. All rows are then shown in the DataGridView, despite the code saying that some rows should not be visible. Breakpoints in the code show that the code do arrive at the Rows.Visible = False events. Despite all rows beeing shown a Watch in the debugger shows that:
[code]...
There are two alternative ways of handling the rows in the code. The first attempt (commented away here) is probably the "nicest".
I have a datatable dimensioned as new.I add the columns that I need (during the form's load) I have a datagridview as on object on my form and set the datatable as its source.The table is loaded with values and they display properly.The User closes the form and returns to the 'Main' form. At this point no problems, everything is working great. NOW...The user re-opens the form containing the datagridview It has the values from the previous time it was open, plus the new values ! I have tried several things so when the user goes back into the form it only has the new values, but it always keeps the previous values and appends the new values to it. I have attempted to clear it by adding a line: datatable.rows.clear(); I have activily gone through the datagridview one row at a time and use a statement to clear the cells;
For Each DGVRow As DataGridViewRow In Me.DataGridViewErrorList.Rows DGVRow.Cells.Clear() Next
i have a Datagridview on my forum and when i Populate it it auto creates a empty row at the end of the grid... i have looked online and seen a few post about it but nothing seams to work... i have tryed...
i'm using vb 2005.I have a datagridview binding to a datatable, and user can add new rows to it. i want to enable copy and paste, so i broke the clipboard content into string array, and tried to fill the values in the datagridview.
I had problems when i had to add new row to the datagridview. because if the user clicks the last row (*) to paste the content, i need to add new row to the datatable, however, the current row is also a new datagridview row. If i just use the following code
'dgv is the datagridview 'dt is the binding table dt=dgv.datasource iRow = dgv.CurrentCell.RowIndex
String comes back from the database with a format: '00/00/0000' I need to then compare it to a date that the user has entered in the same format. How do I make the conversion and compare the two dates?
I have been looking for examples to find the string between two strings. This top one works fine;
Public Sub ReadData(ByRef keywordStart As String, ByRef keywordEnd As String, ByVal filename As String) Using reader = New StreamReader(filename)
[Code].....
Now the first one is fine - Ext_Volume is result of the string between the strings <Volume> and </Volume>. <Volume> and </Volume> are unique so this is straight forward.
However the second one - "^FDExp:" is unique, but "^FS" is not unique. There are occurances of "^FS" before and after "^FDExp:".
How do I get the string to search AFTER the occurrence, not before etc?
Is there an easy way to find a certain string within a string and then return the strings that you find as an array?I have written this:
Public Function FindStrings(ByVal strSourceString As String, ByVal strStartString As String, ByVal strEndString As String) As String() Dim StringStartposition As Integer Dim StringEndPosition As Integer Dim Currentposition As Integer = 1
I have this string called time. It's value is in this format: HH:MM:SS The numbers change, but the format stays the same. I want to separtate the code into 3 strings Hour, Minutes, Seconds.
This must've have been asked before but I couldn't locate it. In a mixed code project (VB and C#) we were debugging some old Visual Basic code where a statement as follows could be found:
If Request.Params("xxx") <> "" Then 'do something
I considered this a bug as Request.Params could be null, in which case the statement would've become false which wasn't the idea. So I thought. I just found out, -- probably for the tenth time and I will keep forgetting -- that the following two statements are not equal, while Nothing in VB should be equal to null in C# (thought I):
if(String.Empty == null) // always false If String.Empty = Nothing Then ' always true
Should I dismiss this as a typical Microsoft backward compatibility effort, or should I consider this a huge error in the VB.NET compiler? Does anybody know the Microsoftean opinion on this oddity?
I use a datagridview where the rowheaders frustratingly stay blank after I load the form. If I modify/add/delete anything the rowheaders pop up. then when I sort by clicking on a columnheader the rowheaders become blank again. all these actions (load/add/modify/sort) go through the same refresh function. I can't seem to figure out why the rowheaders sporadically show up. they should stay visible all the time. btw, datagridview.refresh() doesn't work
I have the code below. The code returns a string in (IntersectingPoints) for X and Y. I need X and Y values to be in single and stored in an array to deal with later.[code]...
I'm using the following to populate a listbox from a sql server:[code]Is Available returns true (It's a bit in sql) or false - Is it possible to replace this with something shorter, say a checkbox or tick image?Also, is it possible to only display actual data rather than the whole field including empty characters? I have a few nchar(30) fields, the above seems to include all 30 character spaces.
