VS 2008 : Set A Column To Accept Only Unique Values?
Nov 30, 2009Is there any way to set a column to accept only unique values?(Via Table Definition)
View 2 RepliesIs there any way to set a column to accept only unique values?(Via Table Definition)
View 2 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
I'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]....
Is there a way to get a subset of Unique values in column(1) of a DataView?
View 6 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.
How 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 have a matrix which is in a text file.
ABMS101848 T G
ABMS101848 C H
ABMS101848 A S
SDFR236176 D Q
SDFR236176 2 X
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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.
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 Replieshow to set the limit of a certain column to accept 10 the same inputs only. I have a table named Date and I want to limit its content for the same inputs to 10 only cause 10 person only can have the same date.
View 14 RepliesHow can I block a column from a datagridview to accept only values like hh:mm style and nothing else. And how to handle errors when user is inserting something else than time format?
View 2 RepliesHow do I declare that my column 4 should accept integers only?
View 1 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]...
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 am having a problem on setting the SQL CE table column a field type. What field type does a column that only accepts only two inputs..
Example: If a table has a column named Gender..it should only accepts two types of input...like Make or Female.
just a quick question. I'm trying to code a textbox that will enable a button, only when the value in the textbox is no less than 1. I've tried an if statement with txtBox.Text > 0 doesn't work Will it involve something with Min and Max values?
View 9 RepliesI need help with making a textbox only accept numeric values only, as in setting a timer interval.
View 2 RepliesI am looking into data validation as I need a way of setting a textbox to only accept numeric values. I have had a search for this and it doesn't seem as straight forward as I had hoped.
I have found a couple of possible methods, although the sites which I found them where very unclear on how they actually work. I feel strongly that I should know how all of my own programs work >_>
I have no actually got this to work with my program yet. Are there better methods than this?
Private Sub TextBox1_KeyPress(ByVal sender As Object, ByVal e As System.Windows.Forms.KeyPressEventArgs) Handles TextBox1.KeyPress
Dim allowedChars As String = "0123456789$,"
[Code].....
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 RepliesProblem: I wanted data input text boxes that only accept numerical values between 0 and 999. I could check for this during a later 'save' routine, but instead preferred to warn the user at the input stage; so I chose masked textboxes - setting the mask to "000". However these boxes appear and behave differently. They have a row of 3 underscores - which I don't want - and also seem more difficult to hit with the cursor. How can I get Masked TextBoxes to appear and behave exactly as normal ones?
View 7 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 RepliesFor my database I need to create unique numbers and insert them in the column "ID". Can I add them via a SQL query? The numbers would simply be 0001 to whatever.I'm using the "Show Table Data" gui.
View 7 Replies