Anyone have any ideas what would prevent my data from not be ing able to be bound to my data column? [code]My error says cant bind to column named SellingPrice? I have many other columns ALL binding the same way and other parts of my program recognize SellingPrice ?
View 9 RepliesI'm adding a DateTime DataColumn to a DataTable like this:
Dim colDate As DataColumn = New DataColumn("Date")
colDate.DataType = System.Type.GetType("System.DateTime")
dt.Columns.Add(colDate)
Then when I try to add it to my datatable, if the value is Nothing I get an error saying string was not recognized as a valid DateTime. I'm having trouble getting this to work.
Can anyone demonstrate with an example how to shift the position of a datacolumn in a specific position after it is added at the end of a datatable.For example lets say I have a datatable with 9 columns and 5 rows. Now I added a 10th column. However I need this new column as the 5th column which requires shifting. How do I perform this shifting?
View 3 RepliesI have a form called studentForm which has a studentCombobox, studentTextbox and a studentDatagridView
In the constructor of the studentForm I need to bind studentCombobox to the StudentbindingSource of the main form and to bind studentDataGridView to appropriate binding source in the mainForm.So that this datagrid view displays all the bookings for the studentID currently selected in studentComboBox
studentComboBox.DataSource = MainForm.StudentBindingSource
studentComboBox.DisplayMember = "StudentID"
studentDataGridView.DataSource = MainForm.StudentDataSet
studentDataGridView.DataMember = "Names "
This is the code I wrote in the constructor
I am trying to bind my SQL param's qurey to bind to a table. My problem is i get this error "Fill: SelectCommand.Connection property has not been initialized."
Protected Sub Button1_Click(ByVal sender As Object, ByVal e As System.EventArgs) Handles Button1.Click
If RadioButton3.Checked = True Then
Dim connectionGrid As SqlConnection = New SqlConnection("Data Source=BST;Initial Catalog=dsfs;uid=dfsdf; pwd='dsfsf'")
Dim commandgrid As SqlCommand = New SqlCommand()
[code]....
I have a DataTable that I am creating and binding to a GridView. Currently the headers do not have any spaces and it makes it hard to read. I want to space them out but I'm having a minor issue.[code]I know that I can set the HeaderText in the columns declaration like below, but I won't know how any columns I am going to have. And would rather the columns be generated automatically. [code]
View 2 RepliesHow do I go about adding a ButtonColumn to a DataTable.
I am basically using a DataTable as the DataSource of a DataGrid and need to add a ButtonColumn to the DataTable so that when I DataBind it to the DataGrid it all works.
Although when I try
dt.Columns.Add(buttonColumn)
This is not allowed. It has to be a basic DataColumn.
Is there a way to change when an expression in a datacolumn is evaluated?
I'm trying to make a simple total function which sums the values of a particular column in a data grid. Normally the expression is evaluated when I leave from the datagridview, but I wish it to be evaluated when the row is changed.
in my datatable I've a String.Byte[] column which contains the array of bytes of an image. So, when the datatable is binded to the datagrid, I can see the picture, if present, and the red cross if is not presente. So I can remove the red cross, by assign a value to the DefaultValue property of the datacolumn. But what default value I've to assign?? I tried with system.dbnull.value but the red cross is still present.
View 8 RepliesFirst of all - It`s my first post here so welcome I have a short question.I have an array with strings values, and a datacolumn with values of the same data type. The question is - what is the most efficient method to find values which are in the array, but aren`t in the datacolumn?
View 18 RepliesThis is the code I have:
Sub Main()
Dim dts As New DataSet
Dim da As New SqlDataAdapter
Dim SolTabla As New DataTable
[code]....
For example, I want to access the second cell value in "Columna". How can I do this with no using a Datagrid?
I have a dataset with a number of data columns, due to sizing issues I've updated a number of the varchar columns from say VARCHAR(20) to VARCHAR(50).I'd like the DataTable to automatically grab the new column information, is this possible? I'd rather not go through each column in the table and update the length.
View 1 Repliesi read an article about datacolumn.expression property here [URL]. this is really great. but i was just wondering, for my case i want to use my custom function to use in the expression. basically, on my datatable i added an unbound column AGE. when i display records, i just want the age textbox to be populated with the computation of the person's age based on birthdate.
View 7 RepliesPrevent an empty column in Excel to be loaded into a dataset column?
View 3 Replieshow to prevent an empty column in Excel to be loaded into a dataset column?
View 10 RepliesI defined a DateTime datacolumn in a datatable dt as [code]]....
View 5 RepliesI'm using MySQL to store some numbers. One of the columns in the database is defined as unique, but it does allow multiple NULL-values. That is exactly how I want it.ut when I'm trying to load the data into my strongly typed DataSet, I get a error saying that a constraint fails... I do understand why that happens (several rows with NULL-values in a unique column), but is it a way to keep a DataColumn in vb.net unique, but still allow several rows with NULL-values like in MySQL?
View 2 Repliesdatacolumn expression subtracting dates and taking to datagridview
View 1 RepliesI 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 RepliesI am currently working with a datatable and I want to be able to show richtext in a column of the table. First question can this be done? I can force the column to be Type Of richtext box. However, when I try to view/display the table, I get something like..."System.Windows.Forms.RichTextbox, Text: Text That I have added" in the column.
Is there a way that I can get it to show the rich text in a cell of a datacolumn of a datatable?
I have a datatable which loads data from an Excel Spreadsheet. One of the columns in the Excel SpreadSheet was of type "Date/Time" in which date values are stored. Now I appended the datatable with three new rows and I wanted to store string values in these rows using the code below. However due to the fact that one of the columns are date/time type, an error is generated as date/time column does not accept string value. I have two questions
a. Is it possible to store string value in date/time DataColumn?
b. Is there a remedy to this situation? [code]
I have a DataColumn and call the MaxLength Property on it to get the length of data that can go into a field ... but it always returns -1 (yes even on a string field).
View 8 RepliesI have a DataTable with two DateTime columns: "start_time" and "end_time".Now, I want to add a third column that calculates the difference between the two DateTimes. But I can't seem to figure out how. I've tried to set the .Expression-value to "start_time - end_time", but it says that "-"-operator is not allowed on DateTime.
View 4 RepliesI'm currently developing an application with a reasonably complex DataGridView that allows the user to build the lines of a sales document: Quantitiy, Description, Price, etc with some additional fields to help calculate price based on cost or discount i'm sure you get the jist - all this means we're not just diplaying data but adding and manipulating it - It also means there's mainly decimal fields, nit just simple text fields
Now, i'm new to VB.net, so i've perhaps done things a bit backwards during my learning curve, namely designing and coding my DGV before creating the underlying database table and binding to it - so as i'm sure you can image there's a bit recoding to do to allow for the fact that it's now bound to a datasource.
I'd got the DGV working just how a wanted it to, but now that i've bound it to a datasource i'm hiting multiple problems with: Formating the appearance of figures in the DGV Problems with blank fields while enering data (before the i try to save the data back to the database) How the DGV is functioning - it seems to behave differently when adding lines to a new sales document than it does when adding lines to an existing sales document
And given that when saving edits to an existing line i need to provide a valid update command i'm begining to think that it might be easier to scrap the databinding altogether and just Select, Add and Edit the database with code rather than binding the DGV in the IDE
I've read various threads about avoiding databinding due to it's limitations, but i've also read that it's far better in later versions of Visual Studio and .net. and i'm using VS2010
I'd just like some advise as to whether my gut feeling is right or whether i should persevere with databinding the DGV. i've noticed some quirks of databinding while working with other controls such as text and combo boxes, but i've overcome these and the result seems to be easier than coding the data transfer manually.
But i'm really struggling with databinding the DGV and the fact that i'm dtatbinding to a seperate table to the rest of the controls is leaning me away from databinding
I have added a column to a Datatable called CallsPerDay which is there to tell me how many telephone calls have been made on a particular day or days.Is there a datacolumn.expression which will allow me to Filter on the day, count the rows and then populate this added column with the result.
View 1 RepliesI am trying to write following expression on a datacolumn. But it results in error:Replicate('*', nLevel) + NameWhere: Replicate() is a user defined function (in a module). nLevel and Name are two other columns in same data table.
View 3 RepliesI'm trying to assign some parameters for a stored procedure with some values that are stored in a data table. in the code, I can set the parameter values to the data table, and give a column header or index without issue, but when it tries to execute at runtime it bombs out.the error I get is a variation on "Failed to Convert Parameter Value from a DataColumn to a String" depending on exactly how I try to assign the value.the data types are all correct elsewhere in the code.
my code for this bit is
Try
ConnectionAttempt.Open()
Try
With NewYearCommand_Dates
[code]....
other things I've tried to get this to work are all variations on the .Value=dates bit, such as
.Value=dates(0) (so using column index)
.Value=dates.columns(0) (again using column index)
I've also tried declaring variables, and setting their values to the values in the columns, but the code returns an error saying that "Value of type 'System.Data.DataColumn' cannot be converted to string".I should point out that i'm doing this for 3 tables at once in this sub, 2 of them will only have a single row of data, but the third has an indeterminate number of rows.I'm afraid I don't know what else to do. I'm lead to believe by my mate and my lecturer that this should work, and of course it will work, but the evidence says otherwise.
Is there an equivalent to C#'s MVC [Bind(Include="Title,Description")] in VB?
View 1 RepliesI have an unbound DataGridView
I want to be able to add just a few rows in one specific column, save this to My.Settings, and be able to load those words back into the DGV at the press of a button, make any changes, then re-save in My.Settings.
I don't want to have to bind my DGV to a source.
I have a vb winapp that reads data from an xml file; this is the code:
Dim doc As New XmlDocument
Dim ds As New DataSet
ds.ReadXml(Application.StartupPath + "Nomi.xml")
Dim dt As New DataTable
dt = ds.Tables(0)
But when i debug i get an error System IO cannot finde file C:...DebugNomi.xml