I am trying to write following expression on a datacolumn. But it results in error:Replicate('*', nLevel) + NameWhere: Replicate() is a user defined function (in a module). nLevel and Name are two other columns in same data table.
View 3 Repliesi read an article about datacolumn.expression property here [URL]. this is really great. but i was just wondering, for my case i want to use my custom function to use in the expression. basically, on my datatable i added an unbound column AGE. when i display records, i just want the age textbox to be populated with the computation of the person's age based on birthdate.
View 7 RepliesIs there a way to change when an expression in a datacolumn is evaluated?
I'm trying to make a simple total function which sums the values of a particular column in a data grid. Normally the expression is evaluated when I leave from the datagridview, but I wish it to be evaluated when the row is changed.
datacolumn expression subtracting dates and taking to datagridview
View 1 RepliesI am trying to build a filter string for my DataView, but I have run into a problem. My underlying DataTable contains values that are formatted when displayed in my DataGridView.For example, if the DataColumn contains 1.52 and the DataGridViewColumn.DefaultCellStyle.Format = "n0" then 2 is displayed.So the user sees 2, then sets the DataView.RowFilter = "DataColumn = 2", and no DataRows are returned. Is there a way to format the DataColumn in the RowFilter string? For example, DataView.RowFilter = "FORMAT(DataColumn, "n0") IN (2, 4)". This filter string should return 3 rows. If not, can LINQ do this?
View 5 RepliesI have a DataTable with two DateTime columns: "start_time" and "end_time".Now, I want to add a third column that calculates the difference between the two DateTimes. But I can't seem to figure out how. I've tried to set the .Expression-value to "start_time - end_time", but it says that "-"-operator is not allowed on DateTime.
View 4 RepliesI have added a column to a Datatable called CallsPerDay which is there to tell me how many telephone calls have been made on a particular day or days.Is there a datacolumn.expression which will allow me to Filter on the day, count the rows and then populate this added column with the result.
View 1 RepliesI got this Error. below is my code.
GenerateTheList is function.Need help
Private Sub buttGenerate_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles buttGenerate.Click
Dim thread1 As New Thread(New ThreadStart(GenerateTheList))
thread1.Start()
End Sub
While looking in the dataset designer for a database table I am doing in visual basic 2008 I found a line for expressions under the property menu for a specific column. I need to know the code that I would put in this expression line so that this column adds up the numbers I input into three other columns and displays that number in the column. I need it to automatically calculate this for each row in the database table.
View 13 RepliesI am using Flee to build a formula builder. It works great but the only problem I'm facing is that Flee doesn't understand Generic Methods I guess. I have a function called IIf declared in the expression context I'm using. [code]How can I work around this. I mean cannot , in sense, write all possible overloads of the function of all .net primitive types. What approach should I take.
View 1 RepliesFrom this code
[Code]...
If I put New Action(AddressOf PrivateMesage), then I get the following error: Bounds can be specified only for the top-level array when initializing an array of arrays. on the following code
[Code]...
I just want to ask if it is possible to create a function that accepts an expression into its arguments. Just like what IIF do. Ex: Dim strResponse as String = IIF(Msgbox("Select Yes or No", vbYesNo) = vbYes, "Yes", "No") I forgot the code, but its the thought that counts.
View 1 Replies1.print the cars which are fast moving cars.
i have written this code but it shows message Cannot have aggregate function in expression[code]...
Should I be concerned about the performance of the Compile method here?[code]...
The reason I want the lambda expression is because I want that function to be able to get all the way through LINQ-to-SQL to be converted to SQL. The reason I want the direct version is because I have other code that I want to validate individual serial numbers before submitting changes. And I fear that GetValidSerialNumbers.Contains(serialNumber) will execute a more-complex-than-necesssary query.
i want to set a complex column expression truncate(cdbl(Today()-date2)/30)*(parent(parentchild).field1/parent(parentchild(filed2)))but truncate function is not available !
View 12 RepliesHaving problem understanding Delegate error. Error says expression expected, How do I fix?Here is the offending line (#259)....
mylist.ForEach(Delegate Function(P As linkItem) As System.Char[] )
Here is the entire code.
<script language="VB" runat="server">
Function sectionTitle(ByRef f As String)
'Open a file for reading
[code]....
y have this class
Private Class MyClass
Public Property propertyOne() as String
Public Property propertyTwo() as String
[code].....
I must convert string data from a CNC that is arithmetic expression to a number that I can use in a VB application that I wrote. The following is what I get out of the cnc. [18722*65536+19377]/67108864. I need to evaluate this expression in my VB ap. The format of the string is not always the same as what I have illustrated.
View 2 RepliesI need to execute scripted text formulas. I believe that in VB 6 and/or VBA there was a method EVAL() that did the job, eg: [Code] As it seems, such a method does not exist in VB.NET. [url] The method works fine but due to its comprehensive layout its not that fast (as i need to call it myriad of times) Does anyone have a SIMPLE, FAST, straight forward math expression method? Or anyone knows how to use the old EVAL method in VB.NET?
View 10 RepliesI have a little question about application settings. I have a regular expression in my code which should be customizable by the user so I made an application setting for it. The regular expression is used in a class in the project and has the following value
Dim email_regularex As String
So now I made a new Settings file in my project and gave the following value for this string in the settings file: ^([w-]+(?:.[w-]+)*)@((?:[w-]+.)*w[w-]{0,66}).([a-z]{2,6}(?:.[a-z]{2})?)$ [URL]
So when i do this in Visual Studio 2008, Visual Studio automatically creates a app.config xml file with the right settings in it. But when I start my application and use the regular expression like this:
Dim
myMatch As
Match = Regex.Match(email, email_regularex)
If
[CODE]...
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?
View 7 RepliesWhat I am about to do build is a UI that will allow a power user to build complex queries.
This is non-trivial, but very common. So before I re-invent the wheel, I would like to see if anybody can point me to some already-written free code or release some of their own.
Required:
To be able to specify some 'where-clause' type logic like this: Age>21 and (Citizen=True or HasGreeCard=True) but without having to type the query code, instead, use a UI with constrained options and on-the-fly syntax checking (e.g., no unclosed parenthesis or ending a term with an Operator).
I've seen this type of thing in many line-of-business apps, where you can say 'add condition' and another line appears on the UI like this:
Dropdown of fields Dropdown of ops (=, >, etc) Blank box for entry
And you can add more lines, and the lines are all and'ed, but you can also decide to OR a few, or insert parenthesis (explicity or via indenting), NOT a line, insert, delete, and move lines around, etc.
Not required but nice:
WPF - I could convert from winforms. Extensibility using OO constructs. Validate the sanity of the query. Emit a System.Linq.Expressions expression tree - or similar data structure. If it attempts to execute the query I don't need that; but I don't mind removing it.
I am currently trying to develop a chat application which will work on a LAN, however encountering problems with with adding a user through the registration form, always getting the result :: "Datatype mismatch in criteria expression" I've tried checking and cross-checking the datatypes used in both the database(its a .mdb database,, created in Microsoft Access)this is the code i am using:
dim con as new oledbconnection
dim cmd as new oledbcommand
Public Sub UserReg()
[code]....
everything is done,, such as opening the connection and defining teh data reader, etc as you can see from teh code(which was derived from another question but i made edits to suit my use for it)I also have problems with checking wether a user is online. obviously i will be referring to the table to do that using something like
cmd = new oledbdatacommand("SELECT * FROM Users where isOnline = "Yes")
dim sdr as oledbdatareader = cmd.execute reader
whence it will show a list of all the currently "Online users" but i do not how how to quite refer to it?
I am calling this function when a button is CLICKED and received the error; The name "The" is not permitted in this context. Valid expression are constants, constants expression, and (in some contexts) variables. Column names are not permitted. Unclosed quotation mark after the character string 'True)'.
The function is as follows;
Private Sub Save()
Dim conn As SqlConnection = GetDbConnection()
Dim query As String
Dim cmd As New SqlCommand
I would like to know the equivalent expresion in VB for this C# expression: Container.TotalRowCount > 0 ? Math.Ceiling(((double)(Container.StartRowIndex + Container.MaximumRows) / Container.MaximumRows)) : 0
View 3 RepliesI am working on an application in Visual Basic Express using an Access 2000 database.I am trying to get athe following SQL query to work but get an error in Access.
The query is:
SELECT [ID], [Title], [Author], [Series], [YearPublished], [ISBN], [CoverPrice], [Style], [Condition], [Signed], [Comments], Count([Title]) AS CountOfBooks, Sum([CoverPrice]) AS TotalCoverPrice
FROM tblBooks
WHERE ID=[@ID];
The error is:"You have tried to execute a query that does not include the spec ified expression 'ID' as a part of the aggragate function."
The query works fine without the 'Count' and 'CoverPrice' count and sum to the query.
I'm a new user of VB.Net. I do have doubt on accessing a user defined Function or Sub. In some place of program, I do see the term "Call" when using the Function/Sub. In some other place without "Call". But both works perfectly. May I know the difference between the two.
[Code]...
The main function receives data, uses additional functions to calculates the result and gives it back. But at one point, the function needs data from the SQL Server. I wrote a second UDF, made it visible and deployed it to the SQL Server. I see now two functions under > programmability > functions > scalar value functions:
1. The main function (IsCalcDay) and
2. The function with the data access (IsHoliday)
If I call directly the second function from VST in the debug mode, it works fine, bur if I call it via the main function, the code stops if the connection will be opened. The error is "Data access in this context is not permitted. The context is a function or method that is not marked with DataAccessKind.Read SystemDataAccessKind.Read or a callback to retrieve data from the FillRow method of a table-valued function or a UDT validation method." (translatet from German, probably slightly differnt in English)
VST (2010 prof) and the SQL Server (2008 R2) are running in my virtual W7 maschine.
Here is the code of the second function:
Imports System
Imports System.Data
Imports System.Data.SqlClient
Imports System.Data.SqlTypes
[Code]....
Why can I open the connection if I call the function directly, but it fails if the function is called from another function?
I am getting the error:"Range variable 'sender' hides a variable in an enclosing block or a range variable previously defined in the query expression."for this
Imports System.Data.SqlClient
Imports System.Linq
Public Class Form1
[code]....
I can select any other item from the table without the error. "sender" has the same properties as "receiver" in the SQL table.
In Access, it is easy to call a user defined function in a sql statment, exampleSub AAdim mDb as[code]...
View 5 Replies