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DynamicQueryStringParameter Class

Automatically generates a collection of parameters that is used to create the Where clause for the data source control by retrieving query string values.

System.Object
  System.Web.UI.WebControls.Parameter
    System.Web.DynamicData.DynamicQueryStringParameter

Namespace:  System.Web.DynamicData
Assembly:  System.Web.DynamicData (in System.Web.DynamicData.dll)

public class DynamicQueryStringParameter : Parameter, 
	IWhereParametersProvider

The DynamicQueryStringParameter type exposes the following members.

  NameDescription
Public methodDynamicQueryStringParameterInitializes a new instance of the DynamicQueryStringParameter class.
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  NameDescription
Public propertyConvertEmptyStringToNullGets or sets a value indicating whether the value that the Parameter object is bound to should be converted to null if it is String.Empty. (Inherited from Parameter.)
Public propertyDbTypeGets or sets the database type of the parameter. (Inherited from Parameter.)
Public propertyDefaultValueSpecifies a default value for the parameter, should the value that the parameter is bound to be uninitialized when the Evaluate method is called. (Inherited from Parameter.)
Public propertyDirectionIndicates whether the Parameter object is used to bind a value to a control, or the control can be used to change the value. (Inherited from Parameter.)
Protected propertyIsTrackingViewStateGets a value indicating whether the Parameter object is saving changes to its view state. (Inherited from Parameter.)
Public propertyNameGets or sets the name of the parameter. (Inherited from Parameter.)
Public propertySizeGets or sets the size of the parameter. (Inherited from Parameter.)
Public propertyTypeGets or sets the type of the parameter. (Inherited from Parameter.)
Protected propertyViewStateGets a dictionary of state information that allows you to save and restore the view state of a Parameter object across multiple requests for the same page. (Inherited from Parameter.)
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  NameDescription
Protected methodCloneReturns a duplicate of the current Parameter instance. (Inherited from Parameter.)
Public methodEquals(Object)Determines whether the specified object is equal to the current object. (Inherited from Object.)
Protected methodEvaluateThrows an InvalidOperationException exception in all cases. (Overrides Parameter.Evaluate(HttpContext, Control).)
Protected methodFinalizeAllows an object to try to free resources and perform other cleanup operations before it is reclaimed by garbage collection. (Inherited from Object.)
Public methodGetDatabaseTypeGets the DbType value that is equivalent to the CLR type of the current Parameter instance. (Inherited from Parameter.)
Public methodGetHashCodeServes as the default hash function. (Inherited from Object.)
Public methodGetTypeGets the Type of the current instance. (Inherited from Object.)
Public methodGetWhereParametersReturns a collection of Parameter objects that are automatically generated for the columns of a table by retrieving query string values.
Protected methodLoadViewStateRestores the data source view's previously saved view state. (Inherited from Parameter.)
Protected methodMemberwiseCloneCreates a shallow copy of the current Object. (Inherited from Object.)
Protected methodOnParameterChangedCalls the OnParametersChanged method of the ParameterCollection collection that contains the Parameter object. (Inherited from Parameter.)
Protected methodSaveViewStateSaves the changes to the Parameter object's view state since the time the page was posted back to the server. (Inherited from Parameter.)
Protected methodSetDirtyMarks the Parameter object so its state will be recorded in view state. (Inherited from Parameter.)
Public methodToStringConverts the value of this instance to its equivalent string representation. (Inherited from Parameter.)
Protected methodTrackViewStateCauses the Parameter object to track changes to its view state so they can be stored in the control's ViewState object and persisted across requests for the same page. (Inherited from Parameter.)
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  NameDescription
Explicit interface implemetationPrivate methodICloneable.CloneReturns a duplicate of the current Parameter instance. (Inherited from Parameter.)
Explicit interface implemetationPrivate propertyIStateManager.IsTrackingViewStateInfrastructure. Gets a value indicating whether the Parameter object is saving changes to its view state. (Inherited from Parameter.)
Explicit interface implemetationPrivate methodIStateManager.LoadViewStateInfrastructure. Restores the data source view's previously saved view state. (Inherited from Parameter.)
Explicit interface implemetationPrivate methodIStateManager.SaveViewStateInfrastructure. Saves the changes to the Parameter object's view state since the time the page was posted back to the server. (Inherited from Parameter.)
Explicit interface implemetationPrivate methodIStateManager.TrackViewStateInfrastructure. Causes the Parameter object to track changes to its view state so they can be stored in the control's ViewState object and persisted across requests for the same page. (Inherited from Parameter.)
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The DynamicQueryStringParameter class is used by pages that are using ASP.NET Dynamic Data features. The DynamicQueryStringParameter class will generate a collection of Parameter objects for the primary keys, foreign keys, and Boolean columns of a table by retrieving query string values.

For primary keys, you can simply add a DynamicQueryStringParameter object without supplying any other parameters. Dynamic Data will generate the parameters for the primary key or keys. For foreign keys or Boolean columns, you must set the Name property to the name of the column you want to filter.

In order to use the DynamicQueryStringParameter class, you must add a DynamicDataManager control to the page and you must register the data-bound control with the DynamicDataManager control by using the DynamicDataManager.RegisterControl method.

See a run-time code example of this feature: Run.

The following example shows how to use the DynamicQueryStringParameter object as filter when displaying data in a GridView control. The GridView control contains a TemplateField object that creates a link that sets the query string value by using the foreign key value.

<%@ Page Language="C#" %>

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">

<script runat="server">

  protected void Page_Init(object sender, EventArgs e)
  {
    // Registers the data-bound control with
    // the DynamicDataManager control.
    DynamicDataManager1.RegisterControl(ProductsGridView);

    // Initializes the URL for the View All link 
    // to the current page.
    ViewAllLink.NavigateUrl = Request.Path;

  }

  protected string GetFilterPath()
  {
    // Retrieves the current data item.
    var productItem = (Product)GetDataItem();
    if (productItem.ProductCategory != null)
    {
      // Creates a URL that has a query string value
      // set to the foreign key value.      
      return Request.Path + "?ProductCategoryID=" 
        + productItem.ProductCategoryID.ToString();
    }
    return string.Empty;
  }

  protected string GetProductCategory()
  {
    // Returns the value for the Name column
    // in the relationship table.    
    var productItem = (Product)GetDataItem();
    if (productItem.ProductCategory != null)
    {
      return productItem.ProductCategory.Name;
    }
    return string.Empty;
  }
</script>

<html xmlns="http://www.w3.org/1999/xhtml">
<head id="Head1" runat="server">
  <title>DynamicQueryStringParameter Example</title>
  <link href="~/Site.css" rel="stylesheet" type="text/css" />
</head>
<body class="template">
  <form id="form1" runat="server">
    <div>

      <h2>DynamicQueryStringParameter Example</h2>

      <asp:DynamicDataManager ID="DynamicDataManager1" runat="server"
        AutoLoadForeignKeys="true" />

      <asp:GridView ID="ProductsGridView" runat="server"
        AutoGenerateColumns="false"
        DataSourceID="ProductsDataSource"
        AllowPaging="true"
        CssClass="gridview">
        <Columns>
          <asp:DynamicField DataField="Name" />
          <asp:DynamicField DataField="ProductNumber" />
          <asp:DynamicField DataField="Color" />
          <asp:TemplateField HeaderText="Category">
            <ItemTemplate>
              <a runat="server" href='<%# GetFilterPath() %>'>
                <asp:Label runat="server" ID="ProductCategory" Text='<%# GetProductCategory() %>' />
              </a>
            </ItemTemplate>
          </asp:TemplateField>
        </Columns>
      </asp:GridView>
      <br />

      <div class="bottomhyperlink">
        <asp:HyperLink runat="server" ID="ViewAllLink" Text="View All Records" />
      </div>


      <!-- This example uses Microsoft SQL Server and connects   -->
      <!-- to the AdventureWorksLT sample database.              -->
      <asp:LinqDataSource ID="ProductsDataSource" runat="server" 
        TableName="Products"
        ContextTypeName="AdventureWorksLTDataContext" >
        <WhereParameters>
          <asp:DynamicQueryStringParameter Name="ProductCategory" />
        </WhereParameters>
      </asp:LinqDataSource>

    </div>
  </form>
</body>
</html>

.NET Framework

Supported in: 4.6, 4.5, 4, 3.5 SP1

Windows 8.1, Windows Server 2012 R2, Windows 8, Windows Server 2012, Windows 7, Windows Vista SP2, Windows Server 2008 (Server Core Role not supported), Windows Server 2008 R2 (Server Core Role supported with SP1 or later; Itanium not supported)

The .NET Framework does not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.

Any public static (Shared in Visual Basic) members of this type are thread safe. Any instance members are not guaranteed to be thread safe.
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