QueryStringParameter Constructors
Definition
Important
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Initializes a new instance of the QueryStringParameter class.
Overloads
QueryStringParameter() |
Initializes a new unnamed instance of the QueryStringParameter class. |
QueryStringParameter(QueryStringParameter) |
Initializes a new instance of the QueryStringParameter class, using the values of the instance that is specified by the |
QueryStringParameter(String, String) |
Initializes a new named instance of the QueryStringParameter class, using the specified string to identify which query-string field to bind to. |
QueryStringParameter(String, DbType, String) |
Initializes a new named instance of the QueryStringParameter class, using the specified query-string field and the data type of the parameter. |
QueryStringParameter(String, TypeCode, String) |
Initializes a new named and strongly typed instance of the QueryStringParameter class, using the specified string to identify which query-string field to bind to. |
QueryStringParameter()
Initializes a new unnamed instance of the QueryStringParameter class.
public:
QueryStringParameter();
public QueryStringParameter ();
Public Sub New ()
Examples
The following example shows how to use the QueryStringParameter constructor to create a new QueryStringParameter parameter and add it to the SelectParameters collection of an AccessDataSource control.
QueryStringParameter empIdParam = new QueryStringParameter();
empIdParam.Name = "empId";
empIdParam.QueryStringField = "empId";
AccessDataSource1.SelectParameters.Add(empIdParam);
Dim empIdParam As New QueryStringParameter()
empIdParam.Name = "empId"
empIdParam.QueryStringField = "empId"
AccessDataSource1.SelectParameters.Add(empIdParam)
The QueryStringParameter object is added to the AccessDataSource control and is declared in an ASP.NET Web page. The ListBox control uses the AccessDataSource control to bind and display data whenever the page is requested with a query string that contains a field that is named empId
and that has a corresponding value.
<asp:ListBox
id ="ListBox2"
runat="server"
DataSourceID="AccessDataSource1"
DataValueField="EmployeeID"
DataTextField="LastName" />
<asp:AccessDataSource
id="AccessDataSource1"
runat="server"
DataFile="Northwind.mdb"
SelectCommand="Select EmployeeID, LastName From Employees where EmployeeID = ?" />
<asp:ListBox
id ="ListBox2"
runat="server"
DataSourceID="AccessDataSource1"
DataValueField="EmployeeID"
DataTextField="LastName" />
<asp:AccessDataSource
id="AccessDataSource1"
runat="server"
DataFile="Northwind.mdb"
SelectCommand="Select EmployeeID, LastName From Employees where EmployeeID = ?" />
Remarks
A QueryStringParameter object that is created by using the QueryStringParameter constructor is initialized with default values for all its properties. The properties are initialized as follows:
QueryStringField is initialized to an empty string ("").
Name is initialized to an empty string ("").
Type is initialized to TypeCode.Object.
DefaultValue is initialized to
null
.
Applies to
QueryStringParameter(QueryStringParameter)
Initializes a new instance of the QueryStringParameter class, using the values of the instance that is specified by the original
parameter.
protected:
QueryStringParameter(System::Web::UI::WebControls::QueryStringParameter ^ original);
protected QueryStringParameter (System.Web.UI.WebControls.QueryStringParameter original);
new System.Web.UI.WebControls.QueryStringParameter : System.Web.UI.WebControls.QueryStringParameter -> System.Web.UI.WebControls.QueryStringParameter
Protected Sub New (original As QueryStringParameter)
Parameters
- original
- QueryStringParameter
A QueryStringParameter instance from which the current instance is initialized.
Remarks
The QueryStringParameter constructor is a protected copy constructor that is used to clone a QueryStringParameter instance. The values of the QueryStringField, Name, and Type properties are transferred to the new instance.
See also
Applies to
QueryStringParameter(String, String)
Initializes a new named instance of the QueryStringParameter class, using the specified string to identify which query-string field to bind to.
public:
QueryStringParameter(System::String ^ name, System::String ^ queryStringField);
public QueryStringParameter (string name, string queryStringField);
new System.Web.UI.WebControls.QueryStringParameter : string * string -> System.Web.UI.WebControls.QueryStringParameter
Public Sub New (name As String, queryStringField As String)
Parameters
- name
- String
The name of the parameter.
- queryStringField
- String
The name of the query-string field that the parameter object is bound to. The default is an empty string ("").
Examples
The following example shows how to create two QueryStringParameter objects by using the QueryStringParameter constructor and add them to an AccessDataSource control's SelectParameters collection. A GridView control displays data if the employee
and country
query-string fields are passed with the request and if they have valid values.
<%@ 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">
private void Page_Load(object sender, System.EventArgs e)
{
MyAccessDataSource.SelectParameters.Add(new QueryStringParameter("employee", "employee"));
MyAccessDataSource.SelectParameters.Add(new QueryStringParameter("country", "country"));
}
</script>
<html xmlns="http://www.w3.org/1999/xhtml" >
<head runat="server">
<title>ASP.NET Example</title>
</head>
<body>
<form id="Form1" method="post" runat="server">
<!-- Use a Query String that includes employee=1&country=USA -->
<asp:gridview
id ="GridView1"
runat="server"
datasourceid="MyAccessDataSource" />
<!-- Security Note: The AccessDataSource uses a QueryStringParameter,
Security Note: which does not perform validation of input from the client.
Security Note: To validate the value of the QueryStringParameter, handle the Selecting event. -->
<asp:accessdatasource
id="MyAccessDataSource"
runat="server"
datafile="Northwind.mdb"
selectcommand="SELECT EmployeeID, LastName, FirstName
FROM Employees
WHERE EmployeeID = ? AND Country = ?">
</asp:accessdatasource>
</form>
</body>
</html>
<%@ Page language="VB"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<script runat="server">
Private Sub Page_Load(sender As Object, e As EventArgs)
Dim param1 As New QueryStringParameter("employee", "employee")
MyAccessDataSource.SelectParameters.Add(param1)
Dim param2 As New QueryStringParameter("country", "country")
MyAccessDataSource.SelectParameters.Add(param2)
End Sub ' Page_Load
</script>
<html xmlns="http://www.w3.org/1999/xhtml" >
<head runat="server">
<title>ASP.NET Example</title>
</head>
<body>
<form id="Form1" method="post" runat="server">
<!-- Use a Query String that includes employee=1&country=USA -->
<asp:gridview
id ="GridView1"
runat="server"
datasourceid="MyAccessDataSource" />
<!-- Security Note: The SqlDataSource uses a QueryStringParameter,
Security Note: which does not perform validation of input from the client.
Security Note: To validate the value of the QueryStringParameter, handle the Selecting event. -->
<asp:accessdatasource
id="MyAccessDataSource"
runat="server"
datafile="Northwind.mdb"
selectcommand="SELECT EmployeeID, LastName, FirstName
FROM Employees
WHERE EmployeeID = ? AND Country = ? ">
</asp:accessdatasource>
</form>
</body>
</html>
Remarks
A QueryStringParameter object that is created by using the QueryStringParameter constructor is initialized with the specified parameter name that identifies the query-string field that the parameter binds to. The Type and Direction properties are initialized with default values.
See also
Applies to
QueryStringParameter(String, DbType, String)
Initializes a new named instance of the QueryStringParameter class, using the specified query-string field and the data type of the parameter.
public:
QueryStringParameter(System::String ^ name, System::Data::DbType dbType, System::String ^ queryStringField);
public QueryStringParameter (string name, System.Data.DbType dbType, string queryStringField);
new System.Web.UI.WebControls.QueryStringParameter : string * System.Data.DbType * string -> System.Web.UI.WebControls.QueryStringParameter
Public Sub New (name As String, dbType As DbType, queryStringField As String)
Parameters
- name
- String
The name of the parameter.
- dbType
- DbType
The data type of the parameter.
- queryStringField
- String
The name of the query-string field that the parameter object is bound to. The default is an empty string ("").
Applies to
QueryStringParameter(String, TypeCode, String)
Initializes a new named and strongly typed instance of the QueryStringParameter class, using the specified string to identify which query-string field to bind to.
public:
QueryStringParameter(System::String ^ name, TypeCode type, System::String ^ queryStringField);
public QueryStringParameter (string name, TypeCode type, string queryStringField);
new System.Web.UI.WebControls.QueryStringParameter : string * TypeCode * string -> System.Web.UI.WebControls.QueryStringParameter
Public Sub New (name As String, type As TypeCode, queryStringField As String)
Parameters
- name
- String
The name of the parameter.
- queryStringField
- String
The name of the query-string field that the parameter object is bound to. The default is an empty string ("").
Examples
The following example shows how to create a QueryStringParameter object by using the QueryStringParameter constructor and add it to an AccessDataSource control's FilterParameters collection. A GridView control displays data if the employee
and country
query-string fields are passed with the request and if they have valid values.
<%@ 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">
private void Page_Load(object sender, System.EventArgs e)
{
QueryStringParameter countryFilter =
new QueryStringParameter("country", TypeCode.String, "country");
MyAccessDataSource.FilterParameters.Add(countryFilter);
}
</script>
<html xmlns="http://www.w3.org/1999/xhtml" >
<head runat="server">
<title>ASP.NET Example</title>
</head>
<body>
<form id="Form1" method="post" runat="server">
<!-- Use a Query String with country=USA -->
<asp:gridview
id ="GridView1"
runat="server"
datasourceid="MyAccessDataSource" />
<!-- Security Note: The AccessDataSource uses a QueryStringParameter,
Security Note: which does not perform validation of input from the client.
Security Note: To validate the value of the QueryStringParameter, handle the Selecting event. -->
<asp:accessdatasource
id="MyAccessDataSource"
runat="server"
datafile="Northwind.mdb"
selectcommand="SELECT EmployeeID, LastName, Address, PostalCode, Country FROM Employees"
filterexpression="Country = '{0}'">
</asp:accessdatasource>
</form>
</body>
</html>
<%@ Page language="VB"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<script runat="server">
Private Sub Page_Load(sender As Object, e As EventArgs)
Dim countryFilter As QueryStringParameter
countryFilter = New QueryStringParameter("country", TypeCode.String, "country")
MyAccessDataSource.FilterParameters.Add(countryFilter)
End Sub ' Page_Load
</script>
<html xmlns="http://www.w3.org/1999/xhtml" >
<head runat="server">
<title>ASP.NET Example</title>
</head>
<body>
<form id="Form1" method="post" runat="server">
<!-- Use a Query String with country=USA -->
<asp:gridview
id ="GridView1"
runat="server"
datasourceid="MyAccessDataSource" />
<!-- Security Note: The AccessDataSource uses a QueryStringParameter,
Security Note: which does not perform validation of input from the client.
Security Note: To validate the value of the QueryStringParameter, handle the Selecting event. -->
<asp:accessdatasource
id="MyAccessDataSource"
runat="server"
datafile="Northwind.mdb"
selectcommand="SELECT EmployeeID, LastName, Address, PostalCode, Country FROM Employees"
filterexpression="Country = '{0}'">
</asp:accessdatasource>
</form>
</body>
</html>
Remarks
A QueryStringParameter object that is created by using the QueryStringParameter constructor is initialized with the specified parameter name, the parameter type, and a string that identifies the query-string field that the parameter binds to. The Direction and ConvertEmptyStringToNull properties are initialized with default values.
See also
Applies to
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