Passing DataContext to Button Event Handler

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  • =?Utf-8?B?UGFvbG8=?=

    #1

    Passing DataContext to Button Event Handler

    How do I pass a DataContext to a button_click event handler. I have the
    following:

    public partial class frmMain : Form
    {
    public frmMain()
    {
    InitializeCompo nent();

    string cnStr =
    @"Data Source=.\SQLEXP RESS;AttachDbFi lename=L:\Works pace\SQL
    Databases\Train ing.mdf;"
    + "Integrated Security=True;C onnect Timeout=30;User
    Instance=True";

    DBDataContext db = new DBDataContext(c nStr); // typed DataContext
    }

    private void btnList_Click(o bject sender, EventArgs e)
    {
    var act_types =
    from a in db.Activities // error: name 'db' does not exist
    in
    // the current
    context
    from t in db.Types // ditto
    where a.Activity_Type == t.Type_Id

    orderby a.Activity_Date
    select new
    {
    a.Activity_Date ,
    t.Type_Desc,
    a.Activity_Dist ance,
    a.Activity_Dura tion,
    a.Activity_Rout e
    };

    dgvList.DataSou rce = act_types; // show query results in
    DataGridView

    }

    Thanks
  • Stefan Hoffmann

    #2
    Re: Passing DataContext to Button Event Handler

    hi Paolo,

    Paolo wrote:
    How do I pass a DataContext to a button_click event handler.
    Use a global variable:

    public partial class frmMain : Form
    {
    DBDataContext _DataContext = null;

    public frmMain()
    {
    InitializeCompo nent();
    string cnStr = @"Data Source=.\...";>
    _DataContext = new DBDataContext(c nStr); // typed DataContext
    }

    private void btnList_Click(o bject sender, EventArgs e)
    {
    var act_types = from a in _DataContext.Ac tivities ...
    }
    }


    mfG
    --stefan <--

    Comment

    • =?Utf-8?B?UGFvbG8=?=

      #3
      Re: Passing DataContext to Button Event Handler

      Stefan: yes, visibility. This hit me while lying in bed this morning. Thx.

      "Stefan Hoffmann" wrote:
      hi Paolo,
      >
      Paolo wrote:
      How do I pass a DataContext to a button_click event handler.
      Use a global variable:
      >
      public partial class frmMain : Form
      {
      DBDataContext _DataContext = null;
      >
      public frmMain()
      {
      InitializeCompo nent();
      string cnStr = @"Data Source=.\...";>
      _DataContext = new DBDataContext(c nStr); // typed DataContext
      }
      >
      private void btnList_Click(o bject sender, EventArgs e)
      {
      var act_types = from a in _DataContext.Ac tivities ...
      }
      }
      >
      >
      mfG
      --stefan <--
      >

      Comment

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