如何在VB中显示来自SQL服务器的查询结果? [英] How to display query results from SQL server in VB?
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问题描述
我想从显示在VB中的SQL Server查询结果。我写了下面的code,但没有得到如何就显示结果;
I am trying to display query results from SQL server in VB. I wrote following code, but not getting how to "Just display the results";
Public Function ConnectToSQL() As String
Dim con As New SqlConnection
Try
con.ConnectionString = "Data Source=(local);Initial Catalog=TestDatabase;Persist Security Info=True;User ID=sa;Password=afm"
Dim cmd As New SqlCommand("SELECT username FROM users WHERE username='user'", con)
con.Open()
Console.WriteLine("Connection Opened")
' Execute Query
Dim reader As SqlDataReader = cmd.ExecuteReader()
While reader.Read()
Console.WriteLine(String.Format("{0}, {1}", _
reader(0), reader(1)))
End While
Catch ex As Exception
MessageBox.Show("Error while connecting to SQL Server." & ex.Message)
Finally
con.Close() 'Whether there is error or not. Close the connection.
End Try
Return reader
End Function
可以在任何一个导向?谢谢
Can any one guide? Thank you
推荐答案
我纠正了一些东西,现在你的函数工作正常,我:
I corrected a few things and now your function works fine for me:
Public Function ConnectToSQL() As String
Dim con As New SqlConnection
Dim reader As SqlDataReader
Try
con.ConnectionString = "Data Source=(local);Initial Catalog=TestDatabase;Persist Security Info=True;User ID=sa;Password=afm"
Dim cmd As New SqlCommand("SELECT username, WindowsLogin FROM users WHERE username='user'", con)
con.Open()
Console.WriteLine("Connection Opened")
' Execute Query '
reader = cmd.ExecuteReader()
While reader.Read()
Console.WriteLine(String.Format("{0}, {1}", _
reader(0), reader(1)))
'NOTE: (^^) You are trying to read 2 columns here, but you only '
' SELECT-ed one (username) originally... '
' , Also, you can call the columns by name(string), not just by number '
End While
Catch ex As Exception
MessageBox.Show("Error while connecting to SQL Server." & ex.Message)
Finally
con.Close() 'Whether there is error or not. Close the connection. '
End Try
'Return reader { note: reader is not valid after it is closed } '
Return "done"
End Function
让我知道,如果你有任何问题。
Let me know if you have any questions.
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