C# - Enable The User To Apply A Custom Filter To A System.Data.DataTable?
Feb 16, 2012
I 'd like to enable the user to apply a custom filter to a System.Data.DataTable.At the moment I have a very simple function like this:
Dim result = dataTable.Select(txtUserInput.Text)
With the filtered results I'd like to do further operations(e.g. Database Update/Delete).Is an sql injection protection needed or is the "Select" function secure?
//Edit:Can the "select" function be abused to manipulate any data in the datatable, execute code, ...? If the only danger is that this function can return to much/to less data there is no problem. But if the data in the dataset gets corrupted it's a real problem.
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Mar 15, 2010
I have a datatable and I apply a filter to the defaultview.rowfilter property of that datatable. If I then loop through the rows collection of the datatable, will I only be able to see those rows that the filter applies to, or will it loop through all the rows?
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Feb 15, 2012
I'm loading a DataGridView from a DataView which collects data from a DataTable. I use the DataView to filter, this is the
Dim dv As New DataView
dv = DataSet4.Tables("TABLA1").DefaultView
dv.RowFilter = "propietario='" + NombrePro + "'"
[code].....
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Sep 1, 2010
I am wondering if it is possible to filter data from a datatable.Sample datatable
Quote:
Sno CatID Nos
1 XYZ 25
[code].....
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Jun 25, 2009
I came across this great article on creating a custom datagridview column which creates a graph-like effect in the cells of a custom datagridview column:[URL]..Does anyone know how you would edit this to format the number in the cell as a percentage? And does anyone know how you would set this up to take 0 values which do not create any graph effects at all.I have been trying to do this but keep getting errors.
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Feb 19, 2010
I added this lines in the form load of DataGridPrinter by Merrion in the codebank..[code]Unable to cast object of type 'System.Data.DataViewManager' to type 'System.Data.DataTable'.
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Dec 31, 2009
every time i run this code i get the same error
Unable to cast object of type 'System.Data.DataTable' to type 'System.Data.DataView'.
the code is
Dim plmExcelCon As New System.Data.OleDb.OleDbConnection
Dim cmdLoadExcel As System.Data.OleDb.OleDbDataAdapter
Dim PrmPathExcelFile As String
[Code]......
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Jun 19, 2009
I want to allow the user to enable or disable a textbox by clicking either a button (enable) or the reverse. (disable) if the user clicks the enable button the textbox should receive the focus.
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Nov 9, 2009
viewManager.DataViewSettings(tableFoood).RowFilter =
""viewManager.DataViewSettings(tableFoood).RowStateFilter = DataViewRowState.OriginalRows
viewManager.DataViewSettings(tableFoood).RowFilter =
"ftype=" & type & ""
In table food, I have different type of food, according I want to display in datagridview but dataview on first time show content of food, not change content in grid.
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Jul 8, 2009
Am in the process of architecting a new windows forms application, and I intend to use Visual Basic 2008 and SQL Server Express 2005. This is my first application in .Net and I really want to observe the best OOD & OOP principles to create an application that is easy to maintain and extend (add new functionality). My issue is in regard to databinding on the UI. From experience, what do you guys recommend to use for databinding? Should I return datasets/datatables from my Business Layer and bind these to UI controls or should I return Business Objects and bind these to UI controls? And what are the pros and cons of each approach?
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Oct 4, 2009
I get the below error Unable to cast object of type 'System.String' to type 'System.Data.DataTable'.This is the code I'm using
Dim str As String = String.Empty
If (Session("Brief") IsNot Nothing) Then
Dim dt As DataTable = Session("Brief")
If (dt.Rows.Count > 0) Then
[code]....
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Jul 7, 2010
I have created a Dictionary class (MyDictionary for the example). I am currently trying to pass MyDictionary into a function, filter it into a new instance of MyDictionary and pass this new instance into another method. When I am attempting to create the second instance from the filtered first instance of MyDictionary via Lambda Expressions and the ToDictionary Method, I am getting the following error:
Unable to cast object of type 'System.Collections.Generic.Dictionary`2[System.Int32,System.String]' to type 'MyDictionary'. I have simplified the example and recreated it in LINQPad and am getting the same error.
Here's the simplified version of my code:
[Code]...
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Feb 15, 2012
I m trying to filter a sql db with many filter criteria which inert the user in textboxes .. i ve tryed this query
[Code]...
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Oct 12, 2011
I would like to know how to filter out system tables and only return user tables .when i run the code it displays lists of system tables with user tables list in combobox.I have just gotten into vb.net and have tried few ways to do this but dont understand well enough.
[Code]....
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Dec 17, 2010
I have imported:
Imports System.Xml.Linq
Imports System.Data.SqlClient
Imports System.Data.DataTableExtensions
[code].....
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Jul 2, 2011
I am working on a project and I want to have a list box with a custom data template populate with user data. My question is, when I click on an item in the list box, how can I tell what item I selected? Basically, if I select "kevin", I want to display his data. If I select Dave, I want to display his data. I do not know how to get the data our after it is bound...
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Jun 2, 2011
[code]This is my Code the error is Class 'System.data.datatable' cannot be indexed because it has no default property.. When i try this code in oledb it works but here it wont..
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Jun 25, 2010
im trying to select some rows based on a criteria, i was wondering is it faster if i create a dataview (based on the criteria) and then loop through the view? or should i loop through the entire datatable and check the criteria manually.
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Mar 11, 2010
i have a datatable with some data, i need to select some of the data, and put that data in a new datatable.
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Sep 10, 2009
I'm new to programming so I would like to know if is there any tutorial about how to make a custom skin for VB .Net 2008 and apply it to a form!?
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Jun 23, 2010
This will sound an unusual question but I'm looking to find a way to reduce the number of colours of an image in a PictureBox from 1,000's to 15 and then apply a custom palette of 15 colours using a closest fit algorithm...
My graphics are never larger that 64x64 pixels generally, so the processing power / overhead needed to perform this operation is relatively small!
The inital algorithm I wrote is very slow and requires me to loop every pixel in the image and loop my palette doing a comparison to find a best fit colour.
Finding a decent method to do an initial colour reduction would be great!
I wondered if there were any inbuilt VB commands for PictureBox, etc that could be used to aid me in doing this...
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May 30, 2010
I moved this from the debugger thread as I got no responses.This may be a better area.I have a problem enabling a Scrollbar on a custom control I have created.The custom control has one component,the scrollbar and an area that I draw upon from an internal datasource.Think something like a textbox.In certain instances,I want the scrollbar to be enabled. The Custom Control's job is to do this when the situtation is appropriate.I have a very simple piece of code here:
If <logic conditions> Then
DataScroll_vscrollbar.Enabled = False
Else[code].....
This code is in my OnPaint routine (along with a bunch of other drawing related stuff).Essentially I've determined that there is more stuff to display than the area of the control and need to turn on the scrollbar to give the user of the control the ability to see later stuff.With the exception of this funny behavior, the control is doing exactly what I want.I step through this and have a watch set.I can step through the set to True, but the Enabled value doesn't change.Even the EnabledChanged event fires (Doesn't on the set to False because it's already False), but the Enabled value is still False.I don't know why.Now here is the really interesting part and may give somebody an idea about what's happening: I can change the Enabled value via the debugger (via the Watch) to True.The EventChanged will fire, and from that point on I can set the Enabled value to either True or False and back again with no problems.
I even did some really crazy testing to see if perhaps the debugger just wasn't showing something.
did something like:
Dim idiot as boolean = false
if <logic> then
idiot = true[code]....
I have set the values to Minimum and Maximum, but the problem remains.
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Apr 21, 2010
I am working on a project that takes an xml schema and xml data files and places them into a DataTable, the 2 files are generated from a working table that i have written to disk. I wish to load these 2 files into a DataTable. Here is What i have
vb.net
Friend Function CreateTable(ByVal tableName As String) As Boolean
Dim table As New DataTable(tableName)
table.ReadXmlSchema(tableName & ".xsd")
[code]....
this however produces the following error on line 3
Quote:
System.ArgumentException was unhandled Message=DataTable 'get_item_list' does not match to any DataTable in source.
get_item_list is the parameter passed into this function (tableName)
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Jul 31, 2011
I'm working on Visual Studio 2010 and I have a Visual Basic 2010 Windows Application. I have a DataSet and in my form i want to give the user the option to "filter" the data he sees on the screen. So, for example, I have:
"Choose Bank Name" - TextBox1
"Choose Car Type" - TextBox2
"Choose Agent" - TextBox3
And so on (9 text boxes more)
Now, the user can filer the bank name and agent only, but he can leave them blank and I want the app to generate an SQL Statement and to change the dataset in real time. I know how to generate the SQL Statement, but i don't know how to change the data set sql string in real time.
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Jan 18, 2011
i have a data set on the data set many data adapters .i add a data adapter in the data set the designer was automatically delete then lot of error was coming and i search in google and i go this method and i do that right click the data set and "Run Custom tool" on that time the designer will automatically created. but when i do that a error was coming "The custom tool 'MSDataSetGenerator' failed. Exception of type 'System.Data.Design.InternalException' was thrown."
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Apr 12, 2010
In the below code, I create a DataTable and filter it. When I use filter1, everything works as expected.When I use filter2, everything works as expected only if the SubsectionAmount variable is less than 10. As soon as I set SubsectionAmount=10, the dr2 array returns Nothing.I can't find what is wrong. Here is the code:
Imports System.Data
Partial Class FilterTest
Inherits System.Web.UI.Page[code]..
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Jun 22, 2010
I want to filter the data that's being displayed to my datagrid once I click the combobox and select a specific value,the selected value will be the item to filter the data that I needed to be displayed in the datagrid.. I'm using a datatable,a combobox and a datagrid..here's my code
Private Sub cboView_Click(ByVal sender As Object, ByVal e As System.EventArgs) Handles cboView.Click
dt = New DataTable
sda = New SqlDataAdapter("SELECT DISTINCT KPIPOSTCODE FROM KKPIGROUP", sqlcon)
sda.Fill(dt)
[code].....
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Jun 17, 2010
[code]When I call da.fill I am inserting all records from my query. I was then hoping to filter them to display only those where the GroupingID is equal to 0. When I run the above code. I am presented with all the data, the filter did not work. Please can you tell me how to get this working correctly.
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Dec 28, 2010
I need filter for multiple values on one column using the DataTable.Select method.
Dim totalFatal As Integer =
m_DataSet.Tables("tblAccidentNonMotorist").Select(String.Format("[AccidentNumber] = '{0}' AND CONTAINS([InjuryClass], '"01" OR "02" OR "03"'", accidentNumber)).Length
[code].....
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Nov 9, 2011
I am writing part of a function that tries to search for a username in a list in a rather broad way (last resort). It seems that LIKE does not like trying to match only the first and last characters.
strCriteria = "somename"
drFilter = tblUsers.Select("User LIKE '" & Strings.Left(strCriteria, 1) & "%" & Strings.Right(strCriteria, 1) & "'")
[code]....
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