Using Compute ("SUM(col1 * Col2)", String.Empty) Add A "WHERE" Type Filter?
Jul 24, 2009
I import my records into dataset1.table(0) I have invoice line items in dataset1 I want the total of all line items for a specific invoice# So I get SUM(col1 * col2) **WHERE invoice# = StrVarInvoice#?
For Each dataRow As DataRow In DataSet1.Tables(1).Rows
netamt = DataSet1.Tables(0).Compute("SUM(unitprce * quantity)", String.Empty)
Next
'My Try but is there a better way?? ? Do I have to loop through all records?
For Each dataRow1 As DataRow In DataSet1.Tables(1).Rows
If dataRow("invoice#") = StrVarInoivce# Then
netamt = DataSet1.Tables(0).Compute("SUM(unitprce * quantity)", String.Empty)
totamt = totamt + netamt
Next
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Jun 28, 2010
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?
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May 14, 2009
I want to calculate variance of a col in my datatable object. If i apply datatable.compute(Var(...)), i gives a negative result. Variance can't be negative. And it I just apply it to half of the data, it works fine. Does datatable.compute has a limited capacity?
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Oct 22, 2011
Using VB.Net If the grid cell value is empty, i am getting error as "Conversion from string "" to type 'Double' is not valid"Code (gridview_CellLeave)
Dim z1, z2, z3, z4 As Int32
If grvList.CurrentRow.Cells(1).Value <> "" Then
z1 = grvList.CurrentRow.Cells(1).Value
End If
If grvList.CurrentRow.Cells(2).Value <> "" Then
[Code]...
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Aug 11, 2010
I have a array of strings and I am looping through them, but the string might be empty so I am trying this:
[Code]...
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Feb 15, 2010
Writing an asp.net mvc app and i have something like this...
Public Class AA
'... has some variables...
End Class
Public Class BB
[code]....
So, now in my program, i just want to copy object of type AA to an empty variable of type BB?it makes sense to do this, as i expect all the fields in AA type object to be copied to the newly created BB type object, and the ExtraVariable in the BB type object i would (will) just assign a value to it later (after the copy) on my own time!!I know copying BB type to AA type would not be appropriate as there would be lost data!But im trying to copy AA to BB, I've used both DirectCast and CType to do this, and i keep getting "unable to cast" error!
Note: I'm using vb.net (but can read c#, no problems)
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Feb 24, 2012
I have an app that contains a DataTable that I must summarize. In that table is a Status column (also the index order) and I want to write a loop in which I compute the count for each status. So I wrote my loop and tried to use the compute function of the Datatable class, but I cannot get it working due to some constraints - specifically this...
[Code]....
You can see what I am doing here is grabbing the string value of the Status column, and then trying to get a count of how many records have that Status. My ultimate goal was to cycle the Table and count each time the status changes. But the error I get has to do with where I store the Status in a String, and then issue the second parameter on the Compute function which contains a variable (sumString) and this is where Compute is crashing - and of course, I can see why - my Status is not literal and thus not in quotes.
Generally speaking, is there any way to manage this kind of thing? In my (very) old FoxPro days one would use a macro such as "Status = &sumString" and VFP would translate sumString to its literal. I have never discovered a way to do that in .NET.
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May 15, 2009
I want to get the number of rows where col1 is Null. datatable.compute(count("col1"), "col1 Is Null") always returns 0, and I am sure there are more than 1 rows with col1 is null.
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Feb 4, 2012
I was trying to call a method using Reflection on a method that has a STRING parameter.However a STRING does not have a parameterless constructor.So instead of something like.>>
Option Strict On
Option Explicit On
Option Infer Off
Public Class Form1
[code].....
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Mar 2, 2009
i have a string array that i want to output to a text file. the array size is 10000. i fill the array starting from 0 with some strings. at the end, i only want to show the array from index 256 to the last array that is not empty (for eg. if the array is filled with data from 0 to 2000, i only want the text file to show the data from 256 to 2000 and ignore the remaining strings). Is there any function to do this?t i use is shown below
Dim myArray(10000) as string
Dim strArray As New System.IO.StreamWriter("c:List.txt")
strArray.WriteLine("{0,10}{1,30}", "Index", "Symbol")
[code].....
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May 19, 2010
I have an ASP.NET MVC 2 application in which I am creating a custom action filter. This filter sits on the controllers in the application and verifies from the database whether that function is currently available.[code]....
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Jun 26, 2011
Can some please tell me how to filter integer type value for Visual basic using query. for example: [code]
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Jan 23, 2009
how to set up the filter property to look for more than one file type? msdn says we can set the filter to '*.*' or *.txt' etc, but doesn't say how to specify more than one type.I've tried a pipe delimited string but it didn't seem to work e,g '*.txt |*.log|*.xml'.
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Jan 13, 2011
I would like to write a generic function that would search a List(Of T) for all elements of type TFilter and return a List(Of TFilter) which comprises those elements.
I've tried this:
Public Function FilterList(Of T, TFilter)(ByVal ListToFilter As List(Of T)) As List(Of TFilter)
Return ListToFilter.FindAll(Function(z) z.GetType.Equals(GetType(TFilter))).ConvertAll(New Converter(Of T, TFilter)(Function(z) CType(z, TFilter)))
End Function
But, it gives the following error:
Value of type 'T' cannot be converted to 'TFilter'.
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Jan 3, 2012
given the following class structures:[code]I add the following property to MyList, trying to answer questions like "find out the number of elements with specified type, say Derived1, inside MyList?"[code]
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Oct 24, 2009
We know that the following statement is TRUEdue to my experienceForgive for my ignorance, I have no Reference for these.
Const IsDirectory = 32 'Is DirectoryConst IsFile = 64 'Is FileConst IsDirectoryAndOrFile = 96 'Is Directory And Or File
<All Libraries>
[code].....
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Jun 4, 2011
I have an array set up to receive the names of forms when they open. The form name is sent as a Form not a String therefore when I run my code I cannot check for whether the field is empty in the normal way (ie. array(1) = "") as the "" are only usable with strings!
Dim Forms(24) As Form
Dim i As Integer
Dim Free As Integer = -1
[CODE]...
I only need a solution to do the same as array(1)="" but for windows forms.
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Oct 27, 2011
We have a typelib where we define some constants. One of our sets of constants is created using the module keyword:
module MyConstants
{
const int Const1 = 1;
};
I use tlbimp.exe in a bat file to generate a primary interop assembly for internal use.If I create a VB .net project and add a reference and browse to the .tlb file and import it, the result I see in the browser window is a class named MyConstants. If I click the class, the right hand pane is empty - the class contains absolutely nothing.
If I add a reference to the primary interop assembly, I also see the class MyConstants int he browser window. When I click the class, the constants show up.This is in Visual Studio 2010 (RTM). Why does VB .NET add reference via brwose to the .tlb file differ in this case? Is this a bug in VB .NET or the tlbimp.exe tool?
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Mar 2, 2009
i have a string array that i want to output to a text file. the array size is 10000. i fill the array starting from 0 with some strings. at the end, i only want to show the array from index 256 to the last array that is not empty (for eg. if the array is filled with data from 0 to 2000, i only want the text file to show the data from 256 to 2000 and ignore the remaining strings). Is there any function to do this? i am using visual basic express 2008. The code that i use is shown below
[Code]...
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Feb 24, 2010
I have a nullable database field of type varchar. I am writing a unit test for a service method that retrieves the value of this field. The service method uses a custom DAL that returns a value of String.Empty if the database field is Null (this is desired behaviour).
[Code]...
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Oct 2, 2009
just found out that replace(string does not do the same as string.replace when my string variable was an empty str the first one returns "nothing" and the second returns an empty string (as expected).just sloppy coding anyhow, it was a function that was converted from classic asp and never rewritten properly. [code]
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Nov 8, 2010
OK I have a base query that is returning a list (ObjectQuery, actually but I don't think it matters) I have about 5 subtypes based on the main type and I need to filter them. Everything works fine until I want the results to be of the main type (not a subclass) Basically I have a query that includes everything, then I filter out the types that are not checked in a checkedbox list. (asp.net) Lets say I have an Entity named Task, and SubTask1 and SubTask2 that inherit from Task
[Code]...
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Feb 27, 2012
I have a VB.NET program with a SaveFileDialog control with the filter set as ".asx|*.asx|.m3u|*.m3u" (without the quotes). It works fine to save a file, but if I then try to save a file with the same name of an existing file and then change the extension in the save as type box, it still thinks I want to save the file as the existing file and asks to overwrite the file, disregarding the newly selected file extension.
I have tried setting the SaveFileDialog.FileName = Nothing after saving a file, so the Save File Dialog Box the File name box is empty, but then I like to click the existing file to get the file name I want, then select a new extension and try to save, but it still asks to overwrite the file with the other extension.
I hope my situation is clear and sorry if it has been already asked a million times...but can anyone point me in the right direction or tell me how I can save the file with the currently selected extension, not the previous selected extension when the file name was entered?
Code:
If SaveFileDialog.ShowDialog = Windows.Forms.DialogResult.OK Then
If Path.GetExtension(SaveFileDialog.FileName) = ".asx" Then
' Code Here to Prepare the CodeASX ...
[code]....
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Aug 18, 2009
I would like to query an Employee by matching First and Last name. Ideally, I'd like to be able to specify that in one EmployeeQueryRq QBFC object.
I think I have a start:
Dim EmployeeQueryRq As IEmployeeQuery
EmployeeQueryRq = requestMsgSet.AppendEmployeeQueryRq()
EmployeeQueryRq.ORListQuery.ListFilter.ORNameFilter.NameFilter.MatchCriterion.SetValue(ENMatchCriterion.mcContains)
EmployeeQueryRq.ORListQuery.ListFilter.ORNameFilter.NameFilter.Name.SetValue(LastName)
Is there any way I can add an additional NameFilter to the same request? Or am I stuck walking a response list for the other criteria (albeit a smaller one limited to containing at least one value)?
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Dec 21, 2009
I'm in the process of porting an old excel addin that was writen in VBA to VB .NET. The Excel addin interacts with a number of external com objects. The code sorta looks like this:[code...]
What I'm trying to do is read the string from the COM object and get it in durr for use later in my program.
That second line results in the exception posted above. If I try casting with CStr/CType I get the same exception.
The visual studio watch window reports the type of hurr.getString as a "System.__ComObject" whereas the VBA watch window reports the type as "Variant/Object/String".
Microsoft.VisualBasic.Information.TypeName(hurr.getString) says the type is "String".
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Mar 11, 2010
my code is :
[Code]...
The error is Value of type '1-dimensional array of string' cannot be converted to 'String'.
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Jun 8, 2009
I have a webpage that has a Telerik RadComboBox on the page. One of the properties of this ComboBox is EmptyMessage, which fills the combobox with a message when an item is not selected. I am binding my combobox to a datasource at runtime and for some reason, it wipes this EmptyMessage away. Is there a way to keep my data items in tact and have the empty message there too?
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May 19, 2010
I'm using VB's StringBuilder, and I was curious what is considered "best practice" for emptying the builder/setting it to a new string. Would it be something like this:[code]or is there a "Better" way?
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Sep 16, 2010
Possible Duplicate: In C#, should I use string.Empty or String.Empty or "" ? I just don't understand the benefits of using String.Empty over "". Aside it being strongly typed its longer.
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Apr 30, 2012
I am storing value in Double. If that value is 0.0, I dont want to display anything.
means,
If Value = 14.0, I want to display Value = 14.0
If value = 0.0, I want to display Value =
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