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
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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]....
I'm retooling an app, and condensing my queries down to one, but to do so, I would like to move the columns for better presentation. I am reporting on errors for particlular equipment, and the user may want to get equipment by errors or errors by equipment. Is there any way to change column order?
View 5 RepliesI 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
I am having a ton of trouble trying to check if a record exists. I continue to get a data mismatch on my command.ExecuteScalar().
Code:
Protected Sub btnRegister_Click(ByVal sender As Object, ByVal e As EventArgs) Handles btnRegister.Click
[code].....
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]
View 3 RepliesWhy 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.
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].......................
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).
View 2 RepliesI 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?
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].....
I'm trying to do an if statement to determine whether a value entered in a text box exists within a column..
View 6 RepliesI 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?
I used this code:
Code:
Friend Sub PopulateCB(ByRef mycontrol As ComboBox, _
ByVal expressionSQL As String)
' DMBD is my data-handling class:
[code]...
Nevertheless, mycontrol remains empty after this.
I have one specific problem, that is relative to DataTable Updates to Database.
Code:
auxDatatable = Mydataset.MyDatatable.GetChanges
Now i'm going to Accept or Reject Changes based on some Criteria. The problem is that I wish to Update Only the Records that in Fact exist on the Database, as you can imagine I was forced to create some Dummy Records in Datatable, to a specific job.
My approach to this issue was to do something like this :
Code:
Private Sub MySub (ByVal auxDatatable As DataTable)
Dim drView As Mydataset.Mydatatable
For i As Integer = 0 To auxDatatable.Rows.Count - 1
[CODE]...
As you can see I tried to Delete the rows that are Dummys, but the rows in fact are not being deleted. As consequence I get an error after that Sub, when i try to make :
Code:
MyTableAdapter.Update(auxDatatable)
This is naturaly caused by the dummy Records.
I have an application where I would like to allow the user to change one field in a datatable but leave the other ones uneditable. I am using a datagridview to do this but I can only make the whole table editable or not. The result should be an order form where you have a determined product and should only be able to change the number of items.
View 2 RepliesI am trying to summarize a datatable based on a primary column and then add certain columns. For example this table
col-1 col-2 col-3
1 AA 2
2 BB
[Code].....
This simply doesn't do anything becuase it thinks the target table doesn't have a primary key.
There is a class in this datalayer that subclasses System.Data.Datatable. So for example if I populated a System.Data.Dataset and then tried to put the first table of this dataset into this class like so:
Code:
Dim dt as new myDatable
dt = ds.Tables(0)
[code]....
I am trying to search a datatable using a compound key. I can create the compound key just fine, but when I go to create an object to pass to the find it give me an error. Below is a sample of my code.
dim lblDT...etc...
Here is where I create the compound key, and it seems fine.
lblDT.PrimaryKey = New DataColumn() {
lblDT.Columns("serialno"), _
lblDT.Columns("type")}
This is where I am trying to create an object to pass to the .find
dim objSearch As New Object() {10643, 28}
It if would work this is how the find would be.
Dim row As DataRow = lblDT.Rows.Find(objSearch)
I have been having trouble finding a good way to do this. Basically what I need to do is take a query from a SQL Server Database and place it into a DataTable (or an array) for manipulation. I've got the connection and everything working, but none of the methods I've tried so far seem to work very well.I need it to compare data with an uploaded CSV file and post on a website.
View 1 RepliesAfter 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
View 1 RepliesProbably a very dumb question but I have a program whereby I create and populate an in memory datatable, which I then add to a data-set. I then run a couple of updates on the dataset and need to know how to then send these updates down into the in memory datatable :Here is a mock up of the code structure following the creation and population of the table :
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I need help with this line of code: Me.avgsalespricetxt.Text = Me.dtsold.Compute("AVG(Convert([Selling Price]),'System.Int32'))")
Here is all the code i have so far, I need to Average a column in my datatable from what i have read "Compute method supports expressions and they support CONVERT function that you could use inside of the expression."
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Source: DataTable
Destination: Access Database Table
I should mention that the DataTable contains data resulted by an SQL SELECT query and it's not related to the "targeted" Access Database Table.
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", ...)
View 2 Replieswhen i run my program and put Jamie in textbox 1 i get the erros Column 'Jamie'.and the line below is highleighted with that erros
Code:
Dim sqlResults As SqlClient.SqlDataReader = _
sqlStatement.ExecuteReader()
here is the code for that sub
Code:
Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
libraryDB.Open()
Dim sqlStatement As New SqlClient.SqlCommand( _
[code].....
Can't add a new column for DataTable
View 2 RepliesI 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
View 3 Repliesi 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
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I have a datagridview and has two columns(UserName and Age), what want to do is to get the UserName that has lowest Age.
View 2 Replies
