Get data from database

i want to have a button and textbox on my form and when i type in a username and click the button i want a lable to show what the password is for that username.

.NET Development12

there are many ways of doing this. The best way in your case would be to use a DataReader. Which database are you using

for ease, lets use SQL, you can change it to OleDb if you are using MS Access for example.

you need:

connection to database

Select command

read results returned executing the Select command

something like this....

import the System.Data.SqlClient namespace then...

private function DoGetPassword(byval username as String) as string

Dim theSqlCommand as new SqlCommand("SELECT [password] FROM [TableName] WHERE [username new SqlConnection(ConnectionString))

Dim theParameter as new
theSqlCommand.Parameters.Add(theParameter)
Dim thePassword as String = String.Empty

try

   theSqlCommand.Connection.Open()
   Dim reader as SqlDataReader = theSqlCommand.ExecuteReader(CommandBehavior.CloseConnection)

   if reader.HasRows = true then

      reader.Read()
      thePassword = reader(0).ToString()

   else

      thePassword = "no username found"

   end if

   theSqlCommand.Connection.Close()

catch ex as SqlException
   'handle exception
   thePassword = "There was an error"
end try

return thePassword

end function

private sub button1_click(byval sender as object, byval e as EventArgs) handles button1.Click

   Me.theLabel.Text = Me.DoGetPassword("MyUserName")

end sub

this should execute the query and get you back the result and place it in the label. Does this work for you of course you need to supply the connectionstring and the correct table/fieldnames.

OK so how do i add data

And i want to do this in Visual Basic Express 2005. Using the SQL server with it.

many ways of doing so. There are a good few examples on how to add data to a database. one would be to fill a dataset, bind it to a datasource/bindable UI component, then call the update method of the DataAdapter or table adapter.

the other would be the "raw" manual approach.

http://forums.microsoft.com/MSDN/ShowPost.aspx PostID=753872&SiteID=1

http://forums.microsoft.com/MSDN/ShowPost.aspx PostID=728535&SiteID=1

With the code you gave me it comes up with a blue underline under the reader and says that it is not declared

Why is this and what do i have to do to get it to work

not sure. Did you import the System.Data.SqlClient namespace as well as this you did declare reader right

Dim reader as SqlDataReader = theSqlCommand.ExecuteReader(CommandBehavior.CloseConnection)

now where this code is it has a blue line under ConnectionString

New SqlConnection(ConnectionString))

the connectionstring would be typically like this:

"Data Source=.;Initial Catalog=DatabaseName;Trusted_Connection=true;"

so...

New SqlConnection("Data Source=.;Initial Catalog=DatabaseName;Trusted_Connection=true;"))

if you are using SQL Express then change the data source to:

"Data Source=.\SQLExpress..........."

www.connectionstrings.com has all the connectionstrings for your needs. the connection string is basically a string that contains details on how/where to connect to to access your database.

Nice example. While I'm a bit more familiar with databasing and code than OP, I'm relatively new to .Net. I prefer hard coding record sets and connections, like your example, to relying on drag and drop data objects.