String Contains Reference To DataTable.Column
Nov 8, 2011
I am using VB.NET and ADO 4.0. Given that I have a string containing a reference to a table.column, can I use the content of the string in a command? [code] I got to the point where I can use the string contents as "reference", it seemed to obvious but [strName] does the trick, partially.When I debug bookableday.room1 remains 0 whilst it should show 6. There might be a conversion issue because the debugger shows me "6" i.s.o. 6 . this is the actual code: [code]
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Mar 24, 2011
I have a database (access) and a listbox which is databound to it etc, and controls the currently selected row in the database.
And i want to check a columns value from the selected row via code, how can i do it? None of the examples on google are recent or for vb.
The column i want to get the value from is
Coulmn name = Related
Column number = 15
The value will be used in a filter so needs to be returned as a string
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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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Feb 7, 2011
I need to sort a DataTable or DataGridView by a column that is a string value, but with null/empty values at the BOTTOM when sorting ASCENDING. The DataTable is NOT populated by a SQL statement, so no order by. If I do
[Code]...
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Mar 5, 2009
I need to sort a DataTable or DataGridView by a column that is a string value, but with null/empty values at the BOTTOM when sorting ASCENDING.The DataTable is NOT populated by a SQL statement, so no order by.If I doDataGridView1.Sort(New RowComparer(System.ComponentModel.ListSortDirection.Ascending))then it throws an exception, saying that the DataGridView is DataBound, which is correct, but doesn't help me, and I want to keep it databound.
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Mar 15, 2009
I have a datatable which has 5 column. It is possible to copy only its 2 column in and save it into new datatable.I used this code but it copies all the 5 column
Code:
Dim qry As DataTable = (From obj In temptable Where obj.Item("Column1") = 0 _
Select obj).CopyToDataTable
i used this one but it is not supported
Code:
Dim qry As DataTable = (From obj In temptable Where obj.Item("Column1") = 0 _
Select obj.item("Column1"), obj.item("Column2")).CopyToDataTable
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Apr 26, 2012
I am finding difficulties to convert a datatable to a new datatable using a reference datatable. My question is confusing and I am not good at explaining things so I drew a picture (see below).I have two datatables on memory and I need to create the third datatable using the second mapping table for reference. The column names are just for example and it can't be hardcoded.
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Jan 7, 2010
This is something that has been bugging me for a while as it is easily fixed but not desirable.I have a DataGridView that has 5 columns. The first is called ID.In vb.net the following line gives an error "Object reference not set to an instance of an object": dgvJobs.Columns("ID").Visible = False ' ERROR dgvJobs.Columns(0).Visible = False ' OK
Obviously using the name is much better than a hard coded value to reference the column but wondering if there is anything i can do to get this to work correctly?The datagridview datasource is BindingSource control with the datasource being a dataset.
[Code]...
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Jan 14, 2009
I am trying to reference a DataTable and I do not know how to achieve this. I would like to assign dtTmp to dtTarget(i) through the reference dtCurr. Is it possible to achieve that in VB.NET?Private dtA, dtB As DataTable
Dim dtTarget() As DataTable = {Me.dtA, Me.dtB}
For i As Integer = 0 To dtTarget.Length - 1
dtTmp = New DataTable()
'Do something to dtTmp
assign the new table to the reference
dtTarget(i) = dtTmp
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Feb 5, 2012
I have a data table, i want to add a new column on that table, the data in that new column will depend in the data from another column. Now i can think of two ways to accomplish this, first is loop through the whole table and do the statements to get my new columns appropriate data. the second approach would be to give the new column an expression, then convert the table to xml (to remove the expression) then convert the xml string back to datatable.
Now, is there any other way around this? what could be the most optimized way in solving this task?
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Oct 27, 2011
After Filling a DataTable in GridView's DataSource . A column with check box Type appears but it created as read only column and I can't enable it or make it editable... even i tried .readonly = false and still can't be edited
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Feb 6, 2011
When I query a DataTable using LINQ, are the rows returned as references? Either way, is it possible to control this behaviour, so that rows are either returned as references or as new rows?My guess is that all objects are returned as references by default, since that seems to be the normal behaviour in most programming languages.
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Dec 30, 2010
I have a string say, str = "system.Int16" I want to add a column in DataTable say, dt = new DataTable()I want DataType for that column as per 'str', i.e. System.Int16 Then How to? dt.Columns.Add("MyColumn", ...)
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Nov 6, 2010
Can't add a new column for DataTable
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Mar 26, 2010
I have a dataset with just 1 datatable and 1 row but with 2 columns.I want to get the value of the 1st column.How can I get it in vb.net
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Apr 27, 2012
i have a Datatable having following result from database
ID Name Class FeeName Amount
9 gumman hgjgh 6Th Fine 0
9 gumman hgjgh 6Th Tution Fee 3000
9 gumman hgjgh 6Th Lebority Fee 500
10 AAdil Hussain 5Th Fine 0
[Code]...
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Oct 15, 2011
I have a sql stored procedure that returns a certain group of columns in my datatable. How can I move (let's say) the column in the first position, to the last position before I export the datatable to excel ?
Dim myConn As New SqlConnection(strConnection)
Dim myCmd As New SqlCommand(strSQL, myConn)
Dim dt As DataTable = New DataTable()
Dim da As SqlDataAdapter = New SqlDataAdapter(strSQL, myConn)
[code]....
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Aug 3, 2011
I have a csv file that comes in I put it into a dataset and do a little manuipulation of the appearance of how the data is presented and then I put it back out into a different csv file that our 3rd party application will except. I was importing it into SQL Server and then doing a select statement to grab the data back out in the format I required. However I'd really like to eliminate the need for the SQL Server use.
So my question is how do I add in the 1st column of a CSV file the column name "KC" with a value of "1" there will only be 1 rows worth of data, mind you it's 55 columns long but there is nothing I can do about that, it's the way it has to be.So do I do this in the DataTable or when I create the CSV file? And how do I do this?
[Code]...
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Feb 7, 2011
Is it possible to have a button column in a data table like there is in DataGridView?
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Mar 16, 2012
I need to limit the amount of columns being returned from a datatable from 14 to 5 or 6. Date, Hour and 3 to 4 decimal columns. Is it possible to do something like a SQL 'Like' to specify which columns I want?
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Jul 22, 2011
So i create a datatable from a table i can't directly view(i.e. using sql server management). I want to find the column names that are in the datatable, what would be the correct way do this?
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May 28, 2009
How to insert a column in datatable at Perticular index in vb 2003.
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Jun 6, 2010
I need to Quarry from Data Table Like
select Name, Address from myDataTable where name = 'x'
and
select distinct(name) from myDataTable
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Jun 2, 2011
What's wrong with my LINQ query ?
Dim s = (From rowItem In i.AsEnumerable() _
Select rowItem("COUNTER")).Sum()
I'm trying to Sum all the value in column 'Counter' in my Datatable. 'Overload resolution failed because no accessible 'SUM' accepts this number of arguments.
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Jun 9, 2012
My problem is that i want to use the Compute method for a datatable.[code]The name of the column of that i want to sumarize is 2012, but it seems that the compute method doesn't recognize it as a column and throw this exception Syntax error in aggregate argument: Expecting a single column with a qualifier 'Child'.It is not possible to me to change the name of the column, what can i do in this case to sumarize the datatable and save it in a variable
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Jan 29, 2010
I have following codes
str2 = "select sno,name from employees where sno =" & Val(Me.TextBox1.Text)
cmd2 = New SqlClient.SqlCommand(str2, con)
da2 = New SqlClient.SqlDataAdapter(cmd2)
dt2 = New DataTable
da2.Fill(dt2)
Now dt2 has two columns as sno and name
But I want to add a 3rd column city type char(80)
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May 20, 2009
i need to do a macro. this is what my excel looks like
1 2 3 4
seq1 name name seq2
abcde vv1 abcdddd
abcxy vv2 abcdlmn
[code]....
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Mar 2, 2011
So strings are reference types right? My understanding is a reference to the string in the heap is passed even when you pass the string ByVal to a method.
String myTestValue = "NotModified";
TestMethod(myTestValue);
System.Diagnostics.Debug.Write(myTestValue); /* myTestValue = "NotModified" WTF? *[code].....
And what is going on under the hood? I would have bet my life that the value would have changed....
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Apr 19, 2010
how I can get rid of this error?
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Sep 25, 2009
i'm trying to get my program to look up a string and find a match in an access database in column "PhoneNumber" and return the value from column "FullName" on the same row to a different string
so it would go like this: (i really don't know much about accessing databases)
Dim PhoneNumber As String
Dim FullName As String
PhoneNumber = TextBox1.Text
FullName =
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