Determine If Datarow Column Exists?
Nov 14, 2008
I have a function in VS2008 VB.NET that creates a dataset and reads field values from that were loaded from a SQL Server 2008 database tables. The tables are from varied sources and in some cases particular column/field names are different. Some use a long name; others use a short name. I need to determine whether a short name or a long name is being used.Pseudo code:If row("ShortName") Exists then ReadDataFrom r("ShortName").ToStringElse ReadDataFrom r("LongName").ToStringEnd If
How would I determine if a particular column name exist in a dataset or datarow?
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Dec 31, 2009
I want to insert a value from loop in datarow so before entering value in datarow, i want to check that a perticular column NAME exist in table or not...please tell me how can i check it. (vb.net preferred).
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Oct 25, 2010
When I use a DataTable as a DataGridView's DataSource, I often have to find which row(s) a user has selected and read specific values from the DataTable (not the DataGridView). I wanted to know if there is any reliable way of determining which DataRow a DataGridViewRow is bound to especially when the user has sorted the DataGridView on a column other than the default order.
Currently, I use code of this sort:
Dim sorting = ""
If DataGrid.SortOrder <> SortOrder.None Then
'get the actual row if the results are sorted'
sorting = "[" & DataGrid.SortedColumn.Name & "]" &
[Code] .....
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Jun 24, 2010
When a user clicks on the add button I do this:-oledrTest = oledstest.tables(0).newrowOn the save I need to know whether they have clicked on the add button or the edit button. In the passed I have set a variable to 1 for add and 2 for edit and on the save if its a 1 I do oledstest.tables(0).add(oledrtest).
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Aug 9, 2010
I'm using the coding below to determin if a certain file exists on the hdd. However there is an error on this line: If FileExists("C:myfile.txt"))="False" then msgbox "False"
it gives me the following error message:End of statement expected.
what am I doing wrong?
[Code]...
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Aug 27, 2010
Below is the code that is adding a toolstripmenuitem at runtime. I do need to check elsewhere to see if it exists. What I have below is incorrect. How would I change the conditional check below?
ToolStripMenuItemFile.DropDownItems.Add("Save")
ToolStripMenuItemFile.DropDownItems(2).Click += New EventHandler(SaveFile_Click)
If ToolStripMenuItemFile.DropDownItems(2) IsNot Nothing Then
ToolStripMenuItemFile.DropDownItems(2).Text = rm.GetString("Save")
End If
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May 23, 2012
Is there a way to determine if a Printer exists?I want to warn my users that a printer doesn't exist before they send reports to print.
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Jan 7, 2009
I wanted to create a login system that would have 3 tabs 1 for regular login, 1 for admin login and 1 for account creation. So far so good. It saves the accounts by saving them in a .urs file in the map called /Users/. However when this map does not exist it will show a error. I would want to know what code or so to put into the form_load which will make my program create the map /Users/ if it does not exist. As im not familiar with all the codes and stuff. The only thing i can come up with is
Mkdir "/Users/"
but then ofcourse it would create the folder users everytime i start the program. not i was still "Hello Worlding" a few days ago, so i really am unfamiliar with any sort of high-skilled programming which i probably dont understand.
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Jan 25, 2010
I would like to check if a URL exists -- without requesting the file. The program needs to check if a PDF or Excel spreadsheet exists at a particular URL. If it does, it might want to download the file, but it should not download it every time.
I currently use the WebBrowser.Navigate method to do this, but it always downloads the file. But I don't want to actually download the .pdf or .xls file, I just want to determine if the URL exists.
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Jan 10, 2010
Im just trying to determine if a website exists when i navigate my webbrowser. via messagebox.Ive tried this so far but it wont work:
Private Sub WebBrowser1_DocumentCompleted(ByVal sender As System.Object, ByVal e As System.Windows.Forms.WebBrowserDocumentCompletedEventArgs) Handles WebBrowser1.DocumentCompleted
If WebBrowser1.DocumentText.Contains("Action canceled") Then
[code]....
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Feb 15, 2010
I am trying to create a function that will determine if a worksheet within the active workbook exits. I have searched many web sites without any luck. Here is the coding I have currently:
HTML
Function SheetExists(ByVal sheetname As String) As Boolean
Dim oWorkbook As Excel.Workbooks
[Code]....
It errors out at Dim oWorksheet As Excel.Worksheet = oWorkbook.Sheets(sheetname).
The error message I am getting is "Object variable or With block variable not set."
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Feb 17, 2010
I have the name of a form in a string variable, e.g. "frmOptions". I want to:
1) get the fully qualified name of the form
2) determine if the form exists in the application
3) create an instance of the form
4) show the form
I know that using reflection I can do #3 this way, but I need to get the fully qualified form name first[code]...
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Apr 27, 2012
I am working with LINQ to XML in VB (although answers in C# are great, too). First off- my code works, so this is not critical. However, I can't help but think that what I'm doing with conditional logic should already be doable using the LINQ query itself. Here's what I've got:
'Get the Description elements in the ResultData section where the value is "Op Code"
Dim opCodes As List(Of XElement) = (From c In xdoc.Descendants("ResultData").Descendants("Description")
Where c.Value = "Op Code"[code].....
Please don't be too critical of my method of locating the sibling nodes- the XML files are produced by a third-party testing device and this is the only generic way to get the values I need. What I'm really looking for here is a better way to handle the If block.
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May 9, 2009
Just like the title says, I have a webbrowser and I need to determine if the element exists or not before I invoke it.
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Dec 7, 2009
Using VS2005, VB.Net, Dot Net 2.0, SQL Server 2000. If have some Columns (varchar and numbers) in a DataRow that I want to set to DBNull in the database. The fields as defined as Nullable in SQL DB table.
I have some fields that are populated when loaded but I want to update to be null using the ADO.Net data objects. If I try and use Row("FieldName") = DBNull.Value a 0 gets written to number fields (not sure what gets written to varchar fields.) What code should be used to update fields to Null using ADO.Net dataobjects?
[Code]...
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Dec 18, 2010
I've been looking around online, and havent quite found what im looking for.I have an unbound DataGridView on my form that has 1 columns ID and NAME, i did a loop to fill in all the ID columns. Then when i loop trough all the ID's, i want to update the NAME column with some data.
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Jan 21, 2011
I need to display a column called Full Name in the my datagridview, but the datasource (datatable) does not have a FullName column. It only has FirstName and LastName columns. I'm setting up my DataGridView like this:
[Code]...
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Sep 13, 2009
I have a windows service which fetches data from various datasources and build a XML file and send it to a webservice. For example first I will get customer details from Oracle Database and build the XML file and then the SQL Server database and build the customer details XML. I am planning to use the same function below to build the customer object irrespective of what the datasource is. But dr("age") column is not available in SQLserver datbase How can I check if a column exists or not.[code]
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Sep 3, 2010
Why am I getting this error, I know there is data there, the code I am using is:
Dim iMaxFields As Integer = oDataReader.FieldCount - 1
Do
sLine = ""
For iColCounter = 0 To iMaxFields
sColOutput = oDataReader.Item([iColCounter]).ToString()
sLine = sLine & sColOutput
[Code] .....
Basically I just want these details put into a HTML table.
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Nov 4, 2009
I am doin a library management project for my college using vb.net and Ms Access as database. I am getting a error No data exists for the row/column. wen i try to select a value in 1st combobox . The first 3 values are working perfectly wen i click on 4th i get error heres da code
Private Sub ComboBox1_SelectedIndexChanged(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles ComboBox1.SelectedIndexChanged
[CODE].......................
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Oct 15, 2008
I have a datagridview which is populated from a datatable. This works fine. But if i run it more then once i get a column name "example" already belongs to this datatable. Ive tried everything to clear all the columns of the datatable and the gridview but still the same
[Code]...
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Jan 22, 2010
I am creating a program which searches saved .htm files for the source codes. I get the source code and do manipulation on the code to pull the values I need into a datagridview.
Is there anyway to search a datagridview column to see if a value exists first, so no duplicate rows of data will be added? I was thinking of making access table and linking the datagridview to it, but i'm not sure how to set the database links up with code (other than the gui), and then still search the column so I don't put in duplicate rows.So far, I have only come up with the way to add the data row by row...
Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
Dim IMsku As String
Dim IMskuitna As String
[code].....
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Jan 20, 2010
I'm trying to do an if statement to determine whether a value entered in a text box exists within a column..
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Sep 15, 2011
I have two tables, dt & dtResults.dt contains 3 columns named: vchInstrumentAnalyteID, bintAnalyteCodeID, & vchAnalyteCode dtResults contains several columns including the columns in dt
I want to get vchInstrumentAnalyteID from the first row in dt and test if it exists in the vchInstrumentAnalyteID column in dtResults. If it exists, I want to use that value from dt to filter rows in dtResults and fill all the filtered rows with data from that row in dt. Then loop to the next row in dt.
I have this code, which is close to what I need, but I can't get it working.
' put analyte data in results table
For Each drA As DataRow In dt.Rows
If
[Code]....
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May 17, 2010
how do you determine cell type of a column?
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Jan 31, 2011
How do i return the column index of an item within a WPF Datagrid, when I click on a cell I'm using Visual Studio 2010/VB.Net?
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Mar 17, 2010
I have a dataset and want to know the data type of a specific column. The GetType returns datacolumn not string or integer etc.iggy!
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Jan 10, 2011
Is there a way to determine column and row with a mouse click on a chart,or at least the column label text.
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Apr 28, 2010
I have two datatables with similar structures that I want to make one existing row to be updated from another datatable.
For example, "tableA" has three columns: "one", "two", and "three"; with "one" being the primary key...
and "tableB" has three columns as well: "one", "two", and "three"; with "one" being the primary key.
Say there is a row on tableA that is different than a row on tableB (with a matching primary key). What I wanted to do, as efficiently as possible, is to take the that row from tableB and replace the one on tableA so it'll be modified.
I'm not sure if there's an easier way of doing that instead of using loops for setting the row's items.
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Feb 26, 2010
I'm using VB 2008 and accessing my SQL Compact Db using the following code:
mSQLceCMD = New SqlCeCommand
mSQLceCMD.Connection = New SqlCeConnection(mStrConn)
mSQLceCMD.Connection.Open()
mSQLceCMD.CommandText = strSQL
[Code]...
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