Get A Subset Of Unique Values In Column(1) Of A DataView?
Dec 16, 2009Is there a way to get a subset of Unique values in column(1) of a DataView?
View 6 RepliesIs there a way to get a subset of Unique values in column(1) of a DataView?
View 6 RepliesI have populated a dataset from a text file and I can display it in a dataview. Can I and if so how do I, select a sub set from this dataset and display it in the dataview?
View 4 RepliesI'm trying to make a method that can get unique values from a specified column of a DataTable. The problem is that the column may be string, integer, etc. I'm not sure what type of variable the (Of T) is.
Private Sub GetColumnUnique(ByVal dbTable As DataTable, ByVal ColumnNumber As Integer, ByVal ColumnType As ???)
Dim results As List(ColumnType) = (From item In dbTable.AsEnumerable Select item.Field(ColumnType)(ColumnNumber)).Distinct.ToList
End Sub
Is there any way to set a column to accept only unique values?(Via Table Definition)
View 2 RepliesI'm using an Infragistics UltraWinGrid with a column of drop-down boxes. I don't want the user to be able to select the same value for multiple rows in that column. Is there a simple (or heck, I'd settle for advanced) way to do this? I'm using VB.NET
-EDIT-
I tried setting a filter on the data source for the drop-down box. But when I did that, the values in the other boxes in that column started disappearing (not the values themselves, but the descriptions that they were supposed to represent, so instead of reading "Information", it just said "1"). All of the cells in a column refer to the same combo box, so if you filter out a value from the data source for one of them, you filter it out for all of them. I'm currently trying to catch a CellChange event and check against all other currently-used values. If it was already used, I would put up a message saying as much and revert back to the old value. However, the value comes back as the previously-saved one, so... not helpful. About to see if I can use the "text" property.
If want to do a DataView.Find on a DataTable that is already 'ORDERED' by the Column I am seaching, so a DataView.SORT should not be necessary, but it throws an Exception if I don't give a .sort command before the .find command. Is there any way to avoid this apparant duplication ? and speed up the search time. Its a very large table - 1 million rows. I am using VB 2010
View 6 RepliesHow can I query a DataTable to find all of the unique values in a column? SQL has the 'unique' or 'distinct' keywords, but I dont know how to do this against a DataTable.
View 6 RepliesI'm using the datagridview. This is the sample data:
[Code]....
How do I parse through the grid to rename the duplicate values in a particular column (in this example it's the l_name field) into such a format?
[Code]....
Unique constraint - these columns currently doesn't have unique values..?? I have created Unique Constraint with 3 columns. My code works perfectly but once - two users @ same time entered same data and somehow it saved in DB; after that incident. This UniqueConstraint gives me error - These columns currently doesn't have unique values. How can I check if user enters this kind of entry or how can I restrict the Entry?
View 2 RepliesDoes anyone know if it's possible to pad a column to the left using the RowFilter property in a DataView? My data comes from a third party via XML which I've converted to a DataSet. I'm inferring the XML schema to set the column datatype. I've converted the column in question to string in order to properly compare any text entered by the user. At the time I populate the data grid I format the column by padding it with zeros on the left side so that it is always 11 characters (Ex: 123456789 becomes 00123456789). This is for legal reasons and not optional. However when using the RowFilter property the zeros in front are obviously not accounted for because they don't exist in the DataSet.
This is what I'm doing currently:
[Code]...
I want create a datatable .In this datatable 2 coloums are percentage and marks .I want to show the maximum percentage record display on first and simultaneosly another racord ?Thats why i take a dataview but dataview could not sort the datatable exam.
Dim view As DataView = dt.DefaultView
view.Sort = "clm_percentage DESC"
dgvStudInfo.DataSource = view
I have filled a datagridview with a dataset using the following code.
Code Snippet
I have a dataview object that is being populated by database fields - so I can sort on these partulular columns by specifying the actual column names without any difficulty. However, I have been asked to add a few more columns to the dataview, and these columns will be calculated columns, not directly derived from an underlying database column.The users want to be able to sort on these new columns as well - even though there is no actual column name I can use to sort.
I have not been able to see where I can sort a dataview based on the actual column integer value used when the user clicks the appropriate heading to sort.
I am trying to do this:
Dim viewdata2 As DataView = fxts.fxtsdata.Tables("clients").DefaultView
Dim viewsorted2 As DataTable = viewdata2.ToTable("clients", True, "Surname", "Name")
[Code]....
I am trying to build a filter string for my DataView, but I have run into a problem. My underlying DataTable contains values that are formatted when displayed in my DataGridView.For example, if the DataColumn contains 1.52 and the DataGridViewColumn.DefaultCellStyle.Format = "n0" then 2 is displayed.So the user sees 2, then sets the DataView.RowFilter = "DataColumn = 2", and no DataRows are returned. Is there a way to format the DataColumn in the RowFilter string? For example, DataView.RowFilter = "FORMAT(DataColumn, "n0") IN (2, 4)". This filter string should return 3 rows. If not, can LINQ do this?
View 5 Repliesam trying to calculate the values in rows in column 6 based on values of column 5. Bellow is the the code I am using I get a run time error about the string not formatted properly
[Code]...
I got a problem with dataview that get data from datatabel (Col1 : ID,Col2: Time) and I'm sorting by Time in desc ... when the values for example {40.21,80.21,70.25,25.2} the dataview sorting them as I need but when one of values goes above 100 for example {40.21,80.21,100.25,25.2} the dataview always sort the highest number is the buttom, I don't know why ..
This is a sample code
Dim dt As New DataTable
dt.Columns.Add("ID")
dt.Columns.Add("Time")
[CODE]...
For each loop through a DataSet, I need to store the values of 2 columns (we'll call them ColumnA and ColumnB) so that I can use them to search the same DataSet again later.The DataSet stores the results of a search and places the value of ColumnA into a ListBox as a new item.When the user clicks on this ListBox item, the application will loop through the DataSet again using the value of ColumnA and the value of ColumnB as criteria to identify the correct row in the DataSet to return.This would be a lot simpler if the value for ColumnA was unique every time, but a value will inevitably be repeated on occasion. That's where ColumnB comes in. This column's value is likely to be unique 90% of the time, and, given the nature of the information in the DataSet, if either column duplicates, the other won't.So I've thought of adding the values for ColumnA and ColumnB into a 2 dimensional dynamic array, but I'm doing something wrong apparently.[code]
View 3 Repliescurrently, what i want to do is, add a column in a table "default" during runtime. Well, I've got that covered already.
The problem is, the column names are actually taken from the users input through a textbox or drop down list and of course, if the same column is added already in the table, it generates an error since it has to be unique.
That is why i wonder if it is possible to know if a column already exists without viewing the form which contains the grid view of that table?
Is there a quick way to put unique value to column in a table? Assuming I want numeric values starting from 0.
View 4 RepliesI have a matrix which is in a text file.
ABMS101848 T G
ABMS101848 C H
ABMS101848 A S
SDFR236176 D Q
SDFR236176 2 X
[Code]...
Alright, I have this Access Database. It has 6 Columns: ID | Class Name | Class Code | Class Room | Grade | Teacher
My ID is the Unique Column that I need to reference back too when Updating my other Fields so I get the correct field.How do I do this? Properly.I've been thinking of a method but I doubt it would work.First I would start off selecting all the ID's and then LOOP through all of them, and then rewrite them to to + 1 Each time I make a Delete, so Each Time it will be a consistent 1 2 3 4 5 6 7 8 9 10 .... etc... Then I can reference from that to my Combo Box Selected Index + 1 to get the Correct Row which corresponds with the Selected Item.Will this work? Or will I still need a Unique Fields that I reference back too.
i need to get only unique value of a column of a datagridview es:
COMLUMN
value1
value2
value3
[code]....
and get only:
value1, value2, value3, value4
how i can do this?? is possibile make a quaery into datagridview?
I have this Access Database. It has 6 Columns: ID | Class Name | Class Code | Class Room | Grade | Teacher My ID is the Unique Column that I need to reference back too when Updating my other Fields so I get the correct field. How do I do this? Properly.
I've been thinking of a method but I doubt it would work. First I would start off selecting all the ID's and then LOOP through all of them, and then rewrite them to to + 1 Each time I make a Delete, so Each Time it will be a consistent 1 2 3 4 5 6 7 8 9 10 .... etc... Then I can reference from that to my Combo Box Selected Index + 1 to get the Correct Row which corresponds with the Selected Item.
is there a way to filter out unique values in a dataview or an array? I currently filter a dataview as such: [code] So now I have a dataview filtering the table, but can I further filter this data to find the unique instances of an item in this table? I eventually have to pass a portion of this table to an array, so if there is a way to find unique values in an array, I can use that.
View 1 Repliesis there a way to filter out unique values in a dataview or an array? I currently filter a dataview as such:
TxtString = "Name = '" & TxtName & "'AND EmpID = '" & EmpID & "'"
dv.Table = dsTestTable.Tables("TestTable")
dv = New DataView(dsTestTable.Tables(0), TxtString, "", DataViewRowState.CurrentRows
So now I have a dataview filtering the table, but can I further filter this data to find the unique instances of an item in this table? I eventually have to pass a portion of this table to an array, so if there is a way to find unique values in an array, I can use that.
how to fix it : These columns don't currently have unique values.
What should i do with my database. I'm using VB.net 2005 and SQL
I am trying to store 5 values and an associated unique key. I need to search for this key and update the 5 associated values. I'm guessing I would use an object as the value but how do I get the values out from the object?
View 19 RepliesI am using a DataGridView that has a filtered dataset and I like to validate a column in a new or changed row via a sub in the partial dataset class so that I can set the errorprovider to an error if the entered value isn't unique.I started out to set the field in SQL server with a unique key and then catch the sqlerror on the form. But data validation is best practice to do in the partial dataset class so I am trying to do it for this particular problem aswell. But after spending a lot of time I am stuck and wonder if it is even possible to do this particular validation in the partial class?
View 9 RepliesI'm using vb.net on vb 2005, I create datagrid view that when i click search button on the main form. It will show datagrid view that I want and when i click OK to select any record, the selected record will show on the desire text box in the main form. The problem is the record i choose is record no. 5 of all 10 record but the Bindingnavigator tools bar show that it's the first record of all 10 and when I click Next record arrow, the error message show that the 'PK column name' is unique and the 'value of the PK from my selected record' is already exist. [Code]
View 1 Replies