To force the user to enter a value in the search field before displaying results in the table control, you can use the Code Customization Wizard example ‘Hide table control until searched’. This customization retrieves records based upon information entered into the search field. Unlike a normal table control that displays results when first displayed on a page, the results are displayed only after the user enters a term into the search field and clicks "Go".

The following code customization example is based on the Orders table in the Northwind database. Add the code customization into the OrdersTableControl class:

.NET Framework 1.1:

<App Folder>Orders\ShowOrdersTablePage.Controls.cs or .vb

.NET Framework 2.0:

<App Folder>App_Code\Orders\ShowOrdersTablePage.Controls.cs or .vb

C#:

public override WhereClause CreateWhereClause() {     WhereClause wc = base.CreateWhereClause();       // If base.CreateWhereClause() returns nothing,     // create a new instance of WhereClause.     if (wc == null)     {         wc = new WhereClause();     }       // If no value is entered in the search area hide the table control     if (!MiscUtils.IsValueSelected(this.OrdersSearchArea) && !(this.InSession     (this.OrdersSearchArea)))     {         // Set RunQuery = False         wc.RunQuery = false;     }     return wc; }

Visual Basic .NET:

Public Overrides Function CreateWhereClause() As WhereClause      Dim wc As WhereClause = MyBase.CreateWhereClause()      If (IsNothing(wc)) Then           wc = New WhereClause      End If      ' If no value is entered in the search area hide the table control      If Not IsValueSelected(Me.${Table}SearchArea) AndAlso _ Not Me.InSession(Me.${Table}      SearchArea) Then           ' Set RunQuery = False           wc.RunQuery = False      End If      Return wc End Function

Step 1: In the Design tab in Iron Speed Designer, locate the 'Go' button for the search control. Double-click the ‘Go’ button to display the Properties dialog. In the Attributes tab, set the button's ‘CausesValidation’ attribute to ‘True’.

Pass-Through Attribute	Value	Type
Button- CausesValidation	True	HTML Encoded

Step 2: In the HTML layout page, add a RequiredFieldValidator control for the search area text box.

<asp:RequiredFieldValidator runat="server" id="OrdersSearchRequiredFieldValidator" ControlToValidate="OrdersSearchAreaTextBox" ErrorMessage="A search value is required." Enabled="True"/>

The RequiredFieldValidator is a .NET control that ensures a value is entered for the field. Be sure to specify values for the ‘ControlToValidate’ and ‘Enabled’ attributes.

Step 3: Build and run your application.

.NET Framework 1.1:

<App Folder>\Orders\ShowOrdersTablePage.Controls.cs or .vb

.NET Framework 2.0:

<App Folder>\App_Code\Orders\ShowOrdersTablePage.Controls.cs or .vb

C#:

public override void OrdersSearchButton_Click(object sender, EventArgs args) {     If (this.OrdersSearchArea.Text == "")     {         BaseClasses.Utils.MiscUtils.RegisterJScriptAlert(this, "UNIQUE_SCRIPTKEY", "Search text         field is empty!");     }     else     {         base.OrdersSearchButton_Click(sender, args);         // Or more code customization can be added     } }

Visual Basic .NET:

Public Overrides Sub OrdersSearchButton_Click(ByVal sender As Object, ByVal args As EventArgs)     If ((Me.OrdersSearchArea.Text = ""))         BaseClasses.Utils.MiscUtils.RegisterJScriptAlert(Me, "UNIQUE_SCRIPTKEY", "Search text         field is empty!")     End If     MyBase.OrdersSearchButton_Click(sender, args)     ' Or more code customization can be added End Sub

Anh is a software engineer at Iron Speed, Inc. He enjoys developing applications with Iron Speed Designer and Microsoft .NET technology.