Databases
StackOverflow2013
Postsdbo
PO
 

Note that there are some explanatory texts on larger screens.

plurals
  1. PO
    primarykey
    data
    text
    <p>User Controls essentially should be unaware of any pages outside the control. The better approach would be to have the control expose properties and events that the page itself (master page or normal) will use to set and retrieve values. Take this simple example:</p> <pre><code> class PassValueEventArgs : EventArgs { public string Value { get; set; } } public event EventHandler&lt;PassValueEventArgs&gt; RequestingValue; public void ControlDoingWork() { PassValueEventArgs e = new PassValueEventArgs(); if (RequestingValue != null) { RequestingValue(this, e); } string fromHandlingPage = "Received " + e.Value + " from a handling page."; } </code></pre> <p>Then whenever the user control should have a value, the page containing the user control can just handle the RequestingValue event and send the value to the user control. Otherwise just expose a public property of the user control, which you can even make databound, for an even easier solution. <br /> Adding a complete example of the event-driven approach: <br /> WebUserControl1EventArgs.cs</p> <pre><code>public class WebUserControl1EventArgs : EventArgs { public double ValueToSquare { get; set; } } </code></pre> <p>WebUserControl1.ascx</p> <pre><code>&lt;%@ Control Language="C#" AutoEventWireup="true" CodeBehind="WebUserControl1.ascx.cs" Inherits="WebApplicationCS1_net20.WebUserControl1" %&gt; Text below will display "Nothing passed from parent page." if the event is unhandled, else will display the square of the number passed if handled.&lt;br /&gt;&lt;br /&gt; &lt;asp:Label runat="server" ID="Label1" Font-Bold="true" Font-Size="Larger" Text="Nothing passed from parent page."&gt;&lt;/asp:Label&gt; </code></pre> <p>WebUserControl1.ascx.cs</p> <pre><code>public partial class WebUserControl1 : System.Web.UI.UserControl { public event EventHandler&lt;WebUserControl1EventArgs&gt; RequestingNumber; protected void Page_Load(object sender, EventArgs e) { ControlDoingWork(); } private void ControlDoingWork() { if (RequestingNumber != null) { WebUserControl1EventArgs e = new WebUserControl1EventArgs(); RequestingNumber(this, e); Label1.Text = (e.ValueToSquare * e.ValueToSquare).ToString(); } } } </code></pre> <p>WebForm1.aspx</p> <pre><code>&lt;%@ Page Language="C#" AutoEventWireup="true" CodeBehind="WebForm1.aspx.cs" Inherits="WebApplicationCS1_net20.WebForm1" %&gt; &lt;%@ Register src="WebUserControl1.ascx" tagname="WebUserControl1" tagprefix="uc1" %&gt; &lt;!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"&gt; &lt;html xmlns="http://www.w3.org/1999/xhtml"&gt; &lt;head runat="server"&gt; &lt;title&gt;&lt;/title&gt; &lt;/head&gt; &lt;body&gt; &lt;form id="form1" runat="server"&gt; &lt;div&gt; &lt;uc1:WebUserControl1 ID="WebUserControl11" runat="server" OnRequestingNumber="WebUserControl11_RequestingNumber" /&gt; &lt;/div&gt; &lt;/form&gt; &lt;/body&gt; &lt;/html&gt; </code></pre> <p>WebForm1.aspx.cs</p> <pre><code>public partial class WebForm1 : System.Web.UI.Page { protected void Page_Load(object sender, EventArgs e) { } protected void WebUserControl11_RequestingNumber(object sender, WebUserControl1EventArgs e) { e.ValueToSquare = 3.3; } } </code></pre> <p>WebForm2.aspx</p> <pre><code>&lt;%@ Page Language="C#" AutoEventWireup="true" CodeBehind="WebForm2.aspx.cs" Inherits="WebApplicationCS1_net20.WebForm2" %&gt; &lt;%@ Register src="WebUserControl1.ascx" tagname="WebUserControl1" tagprefix="uc1" %&gt; &lt;!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"&gt; &lt;html xmlns="http://www.w3.org/1999/xhtml"&gt; &lt;head runat="server"&gt; &lt;title&gt;&lt;/title&gt; &lt;/head&gt; &lt;body&gt; &lt;form id="form1" runat="server"&gt; &lt;div&gt; &lt;uc1:WebUserControl1 ID="WebUserControl11" runat="server" /&gt; &lt;/div&gt; &lt;/form&gt; &lt;/body&gt; &lt;/html&gt; </code></pre> <p>WebForm2.aspx.cs</p> <pre><code>public partial class WebForm2 : System.Web.UI.Page { protected void Page_Load(object sender, EventArgs e) { } } </code></pre>
    singulars
    1. This table or related slice is empty.
    1. POReference masterpage variables from control in child page?
      singulars
      1. PTQuestion
    1. PTAnswer
    1. USMike Guthrie
    1. USMike Guthrie
    plurals
    1. This table or related slice is empty.
    1. This table or related slice is empty.
    1. POReference masterpage variables from control in child page?
      singulars
      1. PTQuestion
    1. This table or related slice is empty.
    1. VO
      singulars
      1. PO
      1. This table or related slice is empty.
      1. VTUpMod
    2. VO
      singulars
      1. PO
      1. This table or related slice is empty.
      1. VTAcceptedByOriginator
    1. COThat's a pretty good idea. Could you provide a full example of the above (with a dummy page passing a value to the user control)? I don't get how the user passes the values from page to control using that technique
      singulars
      1. PO
      1. USchobo
 

Querying!

 
Guidance
A row detail

Detail views are divided into sections. All the information in the data section comes from columns in the selected row. The other sections display data from other, related rows.

Related data can be related in a to-one or a to-many fashion. Captions of data related in a to-many fashion link to a list view showing a filtered view of the table.

Try moving around until you find a non-empty to-many entry and click on the label to get to one. You can move back to the root by clicking on the database name in the header.

SQuiL has stopped working due to an internal error.

If you are curious you may find further information in the browser console, which is accessible through the devtools (F12).

Reload