ASP.Net/ADO.net Database/SqlConnection

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Catch data binding exception (VB.net)

   <source lang="csharp">

<%@ Page Language="VB" %> <%@ import Namespace="System.Data" %> <%@ import Namespace="System.Data.Sqlclient" %> <script runat="server"> 

 Sub Button1_Click(sender As Object, e As EventArgs)
      Dim conn As New SqlConnection("Server=foo;Database=pubs;Trusted_Connection=true") 
      Dim cmd As New SqlCommand("select * from authors", conn)
      Try
        Conn.Open()
        DataGrid1.DataSource = cmd.ExecuteReader(CommandBehavior.CloseConnection)
        DataGrid1.DataBind()
      Catch ex As Exception
        Label1.Text = "Could not connect to the database - " & _
                    "please try again later."
      End Try
   End Sub

</script> <html> <head> </head> <body> 

   <form runat="server">
       <asp:Button id="Button1" onclick="Button1_Click" runat="server" Text="Button"></asp:Button>
       <asp:DataGrid id="DataGrid1" runat="server"></asp:DataGrid>
       <asp:Label id="Label1" runat="server">Label</asp:Label>
       
   </form>

</body> </html> 

      </source>


Display of Data in a Table (Grid) Using SQL Objects (VB.net)

   <source lang="csharp">

<%@Import Namespace="System.Data" %> <%@Import Namespace="System.Data.SqlClient" %> <html> <body>

Display of Data in a Table (Grid) Using SQL Objects

Northwind Employees: <asp:datagrid id="dgrEmployees" runat="server" /> <script language="vb" runat="server"> 

   Sub Page_Load()
       Dim strSQL as string = "SELECT FirstName,LastName FROM Employees;"
       Dim strConnection as String = "server=EWANB;database=Northwind; User Id=sa;password=;"
       
       Dim objDataSet As New DataSet()
       Dim objConnection As New SqlConnection(strConnection)
       
       Dim objDataAdapter As New SqlDataAdapter(strSQL, objConnection)
       
       objDataAdapter.Fill(objDataSet, "Employees")
       
       Dim objDataView As New DataView(objDataSet.Tables("Employees"))
       
       dgrEmployees.DataSource = objDataView
       dgrEmployees.DataBind()   
   End Sub

</script> </body> </html> 

      </source>


Open Sql connection (VB.net)

   <source lang="csharp">
 <%@ import Namespace="System.Data" %>

<%@ import Namespace="System.Data.SqlClient" %> <script language="VB" runat="server"> 

 Sub Page_Load()
  " Dim strConnection as String = "user id=sa;password=;"
   "strConnection += "database=northwind;server=EWANB;"
   "strConnection += "Connect Timeout=30"
  
   Dim strConnection as String = "Data Source=whsql-v08.prod.mesa1.secureserver.net;Initial Catalog=DB_49907;User ID=nfexuser;Password=password;"
   
   data_src.text = strConnection
   Dim objConnection as New SqlConnection(strConnection)
   try
     objConnection.Open()
     con_open.text="Connection opened successfully.
"
     objConnection.Close()
     con_close.text="Connection closed.
"
   catch e as Exception
     con_open.text="Connection failed to open.
"
     con_close.text=e.ToString()
   end try
 end Sub

</script> <html> 

 <body>

Testing the data connection <asp:label id="data_src" runat="server"/>

 <asp:label id="con_open" runat="server"/>

 <asp:label id="con_close" runat="server"/>

 </body>

</html> 

      </source>


Setup SqlConnection (C#)

   <source lang="csharp">

<%@ Import Namespace="System.Data" %> <%@ Import Namespace="System.Data.SqlClient" %> <script Language="c#" runat="server"> 

 void Page_Load()
 {

// string strConnection = "user id=sa;password=;"; 

 //  strConnection += "initial catalog=northwind;data source=EWANB;";
   //strConnection += "Connect Timeout=30";
   string strConnection = "Data Source=whsql-v08.prod.mesa1.secureserver.net;Initial Catalog=DB_49907;User ID=nfexuser;Password="password";";
   data_src.Text = strConnection;
   SqlConnection objConnection = new SqlConnection(strConnection);
   try
   {
     objConnection.Open();
     con_open.Text="Connection opened successfully.
";
     objConnection.Close();
     con_close.Text="Connection closed.
";
   }
   catch (Exception e)
   {
     con_open.Text="Connection failed to open.
";
     con_close.Text=e.ToString();
   }
 }

</script> <html> 

 <body>

Testing the data connection <asp:label id="data_src" runat="server"/>

 <asp:label id="con_open" runat="server"/>

 <asp:label id="con_close" runat="server"/>

 </body>

</html> 


      </source>


Use Trace to debug (VB.net)

   <source lang="csharp">

<%@ Page Language="VB" Debug="true" Trace="true" %> <%@ import Namespace="System.Data" %> <%@ import Namespace="System.Data.Sqlclient" %> <script runat="server"> 

   Sub Button1_Click(sender As Object, e As EventArgs)
     Trace.Write ("Click", "Start")
     Dim conn As New _
          SqlConnection("Server=foo;Database=pubs;Trusted_Connection=true") 
     Dim cmd As New SqlCommand("select * from authors", conn)
     Try
       Trace.Write("Opening connection")
       Conn.Open()
       DataGrid1.DataSource = cmd.ExecuteReader(CommandBehavior.CloseConnection)
       DataGrid1.DataBind()
     Catch ex As Exception
       Trace.Warn(ex.Message)
       Label1.Text = "Could not connect to the database - " & _
                     "please try again later."
     End Try
   End Sub

</script> <html> <head> </head> <body> 

   <form runat="server">
       <asp:Button id="Button1" onclick="Button1_Click" runat="server" Text="Button"></asp:Button>
       <asp:DataGrid id="DataGrid1" runat="server"></asp:DataGrid>
       <asp:Label id="Label1" runat="server">Label</asp:Label>
       
   </form>

</body> </html> 

      </source>
Источник — «http://nfex.ru/index.php?title=ASP.Net/ADO.net_Database/SqlConnection&oldid=1633»