[RESOLVED] VB.NET populate text box using code

[Darraca]

Hi,

I am using VB.NET 2008 and I have made a connection to an SQL Server database using code. I have managed to populate a datagridview control with the contents of a selected table using a query that I passed in. What I want to do now is set a text box to display a selected field from the query using code.

Can anyone tell me how to do this? I used to do this using an adodb.recordset in vb6 but I am new to VB.NET

Thanks

[jmcilhinney]

You don't need to use code. Unless you need something that it can't handle, you should use data-binding. You're already data-binding the DataTable to the DataGridView, so you should just bind it to the TextBox(es) as well:

myDataGridView.DataSource = myDataTable
myTextBox.DataBindings.Add("Text", myDataTable, "MyColumn")

Now, each time you select a row in the grid, the TextBox will be updated with the field value from that row. Any edits you make in the TextBox will be automatically pushed to the underlying DataTable and, as such, the grid too.

If you've bound your grid in the designer then you can bind your TextBox in the designer too, using its (DataBindings) property.

[Darraca]

Hi jmcilhinney,

I didn't use a data table in my code, here's how I got the datagridview control to populate:

Dim conn As SqlConnection
        Dim cmd As New SqlCommand
        Dim da As New SqlDataAdapter
        Dim ds As New DataSet
        Dim SQL As String

        conn = New SqlConnection(m_sConnectionString)
        SQL = "SELECT * FROM tblUsers"

        Try
            cmd = conn.CreateCommand
            cmd.CommandText = SQL
            da.SelectCommand = cmd
            da.Fill(ds, "tblUsers")

            DataGridView1.DataSource = SQLds
            DataGridView1.DataMember = "tblUsers"
            DataGridView1.ReadOnly = True

        Catch ex As Exception
            MessageBox.Show("An error has occurred: " & ex.Message.ToString())
        End Try

I want to get a value from a column called 'Username' from a table called tblUsers. I would like to be able to loop through each record until I match a name and then display that name in a text box.

Thanks

[techgnome]

What do you think a DataSet is? It is a collection of DATATABLES! So even though you didn't explicitly create a datatable variable, you DID create one inside of the dataset implicitly.

So you do have a datatable. That means you can loop through it for each datarow in the datatable... and check the UserName field and see if it matches.

-tg

[jmcilhinney]

I didn't use a data table in my code

Yeah, you did. This:

da.Fill(ds, "tblUsers")

is populating a DataTable named "tblUsers".

[Darraca]

Perfect! Thanks very much! Can I use this method to populate a combobox? I tried ComboBox1.DataBindings.Add("Text", ds, "Table1.Description") but this only added the first item.

Cheers

[techgnome]

Don't use that form of binding... set the datasource (to the dataset) and datamember (to the NAME of the datatable)... the DisplayMember to name of the field to DISPLAY and then the ValueMember to the name of the field that you want to use as the value.

-tg

[jmcilhinney]

I showed how to data-bind a DataGridView, which can display multiple items, and a TextBox, which can display one item. Which is a ComboBox more like?

[jmcilhinney]

Don't use that form of binding... set the datasource (to the dataset) and datamember (to the NAME of the datatable)

A ComboBox doesn't have a DataMember. You have to assign the DataTable itself to the DataSource.

Any time you use the DataBindings property you are performing simple data-binding, while setting the DataSource is complex data-binding. All controls support simple data-binding but displaying all items in a list all at the same time is always going to be complex data-binding.

[Darraca]

Great! thanks, got this working now.
much appreciated

[Darraca]

Just one last thing, what is the best way to assign a value from a database straight to a variable?

Cheers

[jmcilhinney]

Just one last thing, what is the best way to assign a value from a database straight to a variable?

Cheers

To get data from a database you would use ADO.NET to execute a query. You can call Update on a DataAdapter to populate a DataTable, call ExecuteReader on a Command to create a DataReader or call ExecuteScalar on a Command to get a single value. You can then get the data from that DataTable or DataReader and do whatever you want with it, or do whatever you want with that single value. Follow the Database FAQ link in my signature and you'll find resources that show you how to do all three.

[Darraca]

Great! thanks very much, i used the FAQ link and found loads of useful tips.
Thanks again.