Develop Reference

How can I redirect users to a login page after a timeout using C# in ASP.NET?

I’m working on an ASP.NET program with the code behind in C# and connected to a SQL Server database. I want to create a timeout that sends them to the logout page after a certain number of minutes. I’m not using session timeout because the timeout value will vary based on the user’s role. The .aspx page has an UpdatePanel with a DetailsView that has a BoundField for the TimeOut in epoch seconds and another BoundField for the CurrentEpochSecond. These fields are from the database using a select statement. A second DetailsView contains a TemplateField that shows the TimeLeft using a SqlDataSource statement that selects the TimeOut minus the CurrentEpochSecond as TimeLeft. This is triggered by an AJAX timer every 60 seconds and TimeLeft value is shown in the DetailsView.
<asp:DetailsView ID="DV_LoggedInTimeExpires" runat="server"
DataSourceID="SDS_LoggedInTimeExpires" Height="50px" Width="125px"
AutoGenerateRows="False" ondatabound="DV_LoggedInTimeExpires_DataBound"
onitemupdated="DV_LoggedInTimeExpires_ItemUpdated">
<Fields>
<asp:TemplateField HeaderText="TimeLeft" SortExpression="TimeLeft">
<ItemTemplate>
<asp:Label ID="TimeLeftLabel" runat="server" Text='<%# Eval("TimeLeft") %>'></asp:Label>
</ItemTemplate>
</asp:TemplateField>
</Fields>
</asp:DetailsView>
<asp:SqlDataSource ID="SDS_LoggedInTimeExpires" runat="server"
ConnectionString="<%$ ConnectionStrings:ApplicationServices %>"
SelectCommand="SELECT ESET - CRET AS TimeLeft FROM aspnet_Users WHERE
(UserId = #UserId)"
onselecting="SDS_LoggedInTimeExpires_Selecting"
ProviderName="System.Data.SqlClient" >
<SelectParameters>
<asp:Parameter Name="UserId" Type="Object" />
</SelectParameters>
</asp:SqlDataSource>
In the C# code, I’ve tried several statements. When I put
protected void DV_LoggedInTimeExpires_ItemUpdated(object sender,
DetailsViewUpdatedEventArgs e)
{
if (TimeLeft < 1)
{
Response.Redirect("~/Logout.aspx");
}
}
VS shows an error that says: “The name 'TimeLeft' does not exist in the current context”
When I define TimeLeft as an int and change it to
protected void DV_LoggedInTimeExpires_ItemUpdated(object sender,
DetailsViewUpdatedEventArgs e)
{
int TimeLeft;
if (TimeLeft < 1)
{
Response.Redirect("~/Logout.aspx");
}
}
VS shows an error that says: “Use of unassigned local variable 'TimeLeft'”.

Retrieving Current Value from Telerik RadGrid EditFormItem

I have an ASP form created using Telerik's RadGrid control, already binding values from the database and displaying them, with the ability to add and delete entries from the table. I need to add editing functionality, but I've finally run into a block, and I can't find a way past it.
The ASP page contains both the RadGrid and the SqlDataSource I need to use:
<asp:SqlDataSource ID="ContactsSqlDataSource" runat="server"
ConnectionString="<%$ ConnectionStrings:DBConnectionString %>"
SelectCommand="etc..."
UpdateCommand="UPDATE Contacts
SET Salutation=#Salutation,
FirstName=#FirstName,
etc...
WHERE ClientContactID=#ClientContactID" CancelSelectOnNullParameter="False"
onupdating="ContactsSqlDataSource_Updating">
<UpdateParameters>
<asp:Parameter Name="Salutation" Type="String" />
<asp:Parameter Name="FirstName" Type="String" />
etc...
<asp:Parameter Name="ClientContactID" Type="String" />
</UpdateParameters>
<SelectParameters>
<asp:QueryStringParameter Name="GroupID" QueryStringField="ID" />
</SelectParameters>
</asp:SqlDataSource>
etc...
<telerik:RadGrid ID="ContactsRadGrid" runat="server"
AutoGenerateColumns="False" AutoGenerateDeleteColumn="True" CellSpacing="0"
DataSourceID="ContactsSqlDataSource" GridLines="None"
Skin="Windows7" onitemcommand="ContactsRadGrid_ItemCommand"
onitemdatabound="ContactsRadGrid_ItemDataBound"
AllowAutomaticUpdates="True">
<MasterTableView DataSourceID="ContactsSqlDataSource"
DataKeyNames="etc...">
<Columns>
etc...
</Columns>
<EditFormSettings EditFormType="Template">
<FormTemplate>
<asp:HiddenField ID="ClientIDHiddenField" runat="server"
Value='<%# Bind("ClientContactID") %>' />
etc...
<asp:TextBox ID="SalutationTextBox" runat="server" Text='<%# Bind("Salutation") %>' TabIndex="1" />
etc...
<asp:TextBox ID="FirstNameTextBox" runat="server" Text='<%# Bind("FirstName") %>' TabIndex="2" />
</FormTemplate>
</EditFormSettings>
</MasterTableView>
</telerik:RadGrid>
In my code behind, I have:
protected void ContactsRadGrid_ItemCommand(object sender, Telerik.Web.UI.GridCommandEventArgs e)
{
RadGrid grid = sender as RadGrid;
GridDataItem dataItem = e.Item as GridDataItem;
GridEditFormItem editItem = e.Item as GridEditFormItem;
if (e.CommandName == "Delete")
{
etc...
}
else if (e.CommandName == "Update")
{
ContactsSqlDataSource.Update();
}
}
protected void ContactsSqlDataSource_Updating(object sender, SqlDataSourceCommandEventArgs e)
{
GridEditFormItem editItem = (ContactsRadGrid.EditItems[0] as GridDataItem).EditFormItem;
string salutation = Convert.ToString(editItem.GetDataKeyValue("Salutation"));
string firstName = Convert.ToString(editItem.GetDataKeyValue("FirstName"));
etc...
string clientContactID = Convert.ToString(editItem.GetDataKeyValue("ClientContactID"));
e.Command.Parameters["#Salutation"].Value = salutation;
e.Command.Parameters["#FirstName"].Value = firstName;
etc...
e.Command.Parameters["#ClientContactID"].Value = clientContactID;
e.Command.Connection.Open();
e.Command.ExecuteNonQuery();
e.Command.Connection.Close();
}
This is where I finally got to in order to stop getting errors on the SQL execution, however there's one major problem: the values being pushed onto the parameters are the old values, the ones that were already in the database, not the values I've entered in the EditFormItem. If I hardcode something onto a parameter (eg, append ".com" onto email), the alteration is correctly reflected in both the database and the table after the "Save" button in the edit form is clicked. Without the manual edit, no changes occur, because the database is simply being updated with the values that were already present.
How can I get the current values in the edit form?
(I'm not opposed to getting this done in some way other than the DataSource_Updating event, that's just the solution I came up with which was closest to correct. I do need to stick with the RadGrid, though.)

I managed to find a resolution to this issue. In the first part of ContactsSqlDataSource_Updating, I now have:
string salutation = (editItem.FindControl("SalutationTextBox") as TextBox).Text;
string firstName = (editItem.FindControl("FirstNameTextBox") as TextBox).Text;
etc...
string clientContactID = (editItem.FindControl("ClientIDHiddenField") as HiddenField).Value;
The database now updates correctly.

Catching null values on databinding

I have a dropdownlist that is populated from an SQL select statement. The select statement filters for items where the 'bit' is set to false and the items, although still in the database are hidden.
My problem is; when an item is out of stock or hidden (bit = false) the user may still have items that are now hidden so it throws an error. How and where can I catch this, show the original item or set the value to default?
protected void GradeDropDownList_DataBinding (object sender, EventArgs e)
{
var ddl = (DropDownList)(sender);
var a = ((Label)MyDetailsView.FindControl("GradeLabelEdit")).Text;
a = a.Trim();
if (a != "") { ddl.SelectedValue = a; }
}
The select statement;
<asp:SqlDataSource ID="getGrade" runat="server" ConnectionString="<%$ ConnectionStrings:CasesTimeConnection %>"
SelectCommand="SELECT [gradeID], [gradeText] FROM [user_grades] WHERE ([visibleState] = #visibleState)">
<SelectParameters>
<asp:Parameter DefaultValue="True" Name="visibleState" Type="Boolean" />
</SelectParameters>
</asp:SqlDataSource>
In page;
<EditItemTemplate>
<asp:DropDownList ID="GradeDropDownList" runat="server" DataSourceID="getGrade" DataTextField="gradeText" DataValueField="gradeID" OnDataBinding="GradeDropDownList_DataBinding" OnSelectedIndexChanged="GradeDropDownList_SelectedIndexChanged">
</asp:DropDownList>
</EditItemTemplate>
<ItemTemplate>
<asp:Label ID="gradeLabel" runat="server" Text='<%# Bind("gradeText") %>'></asp:Label>
</ItemTemplate>

Retrieve LastModifiedDate while retrieving the records and while trying to update the record check the existing lastModifiedDate value with the one you retrieved. If they are different then throw an alert message / display new quantity.
Thanks
Shashi

Problems with AJAX CascadingDropDown and DropDownList SelectedValue in EditItemTemplate

I am having problem in EditItemTemplate of FormView.
When I use such code in InsertItemTemplate everything works:
<asp:DropDownList ID="Lic_PosiadaczLicencjiIDDropDownList" runat="server"
SelectedValue='<%# Bind("Lic_PosiadaczLicencjiID") %>' />
<asp:CascadingDropDown ID="CascadingDropDown1" runat="server"
TargetControlID="Lic_PosiadaczLicencjiIDDropDownList" Category="Knt_Kod"
ServicePath="~/ManagerLicencjiService.asmx" ServiceMethod="GetKontrahenci">
</asp:CascadingDropDown>
But when I use exactly the same code in EditItemTemplate I am getting an error that SelectedValue is wrong cause it doesn't exists on the list of elements.
I think that the problem is that DropDownList is checked for the values before it is populated by the service. When I run debugger the error occured before breakpoint in the service method.
How to solve this problem?

<rant>I've found the CCD very clunky and full of poorly-documented workarounds</rant> but here is how you do something as simple as selecting a value when filling the ddl. Note that the selected value is not set on the DDL and that it is being passed to the web service where the selecting is done.
<asp:ScriptManager ID="sm1" runat="server"></asp:ScriptManager>
<asp:FormView ID="fv1" runat="server" DataSourceID="yourDataSource">
<EditItemTemplate>
<asp:DropDownList ID="Lic_PosiadaczLicencjiIDDropDownList" runat="server" />
<asp:CascadingDropDown ID="CascadingDropDown1" runat="server"
TargetControlID="Lic_PosiadaczLicencjiIDDropDownList" Category="Knt_Kod"
ServicePath="~/ManagerLicencjiService.asmx" ServiceMethod="GetKontrahenci"
UseContextKey="true" ContextKey='<%# Bind("Lic_PosiadaczLicencjiID") %>'>
</asp:CascadingDropDown>
</EditItemTemplate>
</asp:FormView>
<asp:sqldatasource id="yourDataSource"
selectcommand="select Lic_PosiadaczLicencjiID FROM yourdatabase"
UpdateCommand="Update yourdatabase set Lic_PosiadaczLicencjiID = #newvalue WHERE Lic_PosiadaczLicencjiID = #Lic_PosiadaczLicencjiID"
connectionstring="<%$ ConnectionStrings:yourConnectionString %>"
runat="server"
onupdating="yourDataSource_Updating">
<UpdateParameters>
<asp:Parameter Name="newvalue" DbType="String" />
</UpdateParameters>
</asp:sqldatasource>
code behind:
protected void yourDataSource_Updating(object sender, SqlDataSourceCommandEventArgs e)
{
e.Command.Parameters["#newvalue"].Value = ((DropDownList)fv1.FindControl("Lic_PosiadaczLicencjiIDDropDownList")).SelectedValue;
}
and in your web service where you are getting your data from you need to add the context key to the signature exactly as shown as it is case sensitive. You then check your returned values for the selected value and set selected = true. If you want selected value instead of selected text then check for x.value instead of x.name.
[WebMethod]
public CascadingDropDownNameValue[] GetKontrahenci(string knownCategoryValues, string category, string contextKey)
{
CascadingDropDownNameValue[] results = getdata();
CascadingDropDownNameValue selectedVal = (from x in results where x.name == contextKey select x).FirstOrDefault();
if (selectedVal != null)
selectedVal.isDefaultValue = true;
return results;
}
Hope this helps!

Problem with cascading drop down in asp.net [duplicate]

I am having problem in EditItemTemplate of FormView.
When I use such code in InsertItemTemplate everything works:
<asp:DropDownList ID="Lic_PosiadaczLicencjiIDDropDownList" runat="server"
SelectedValue='<%# Bind("Lic_PosiadaczLicencjiID") %>' />
<asp:CascadingDropDown ID="CascadingDropDown1" runat="server"
TargetControlID="Lic_PosiadaczLicencjiIDDropDownList" Category="Knt_Kod"
ServicePath="~/ManagerLicencjiService.asmx" ServiceMethod="GetKontrahenci">
</asp:CascadingDropDown>
But when I use exactly the same code in EditItemTemplate I am getting an error that SelectedValue is wrong cause it doesn't exists on the list of elements.
I think that the problem is that DropDownList is checked for the values before it is populated by the service. When I run debugger the error occured before breakpoint in the service method.
How to solve this problem?

<rant>I've found the CCD very clunky and full of poorly-documented workarounds</rant> but here is how you do something as simple as selecting a value when filling the ddl. Note that the selected value is not set on the DDL and that it is being passed to the web service where the selecting is done.
<asp:ScriptManager ID="sm1" runat="server"></asp:ScriptManager>
<asp:FormView ID="fv1" runat="server" DataSourceID="yourDataSource">
<EditItemTemplate>
<asp:DropDownList ID="Lic_PosiadaczLicencjiIDDropDownList" runat="server" />
<asp:CascadingDropDown ID="CascadingDropDown1" runat="server"
TargetControlID="Lic_PosiadaczLicencjiIDDropDownList" Category="Knt_Kod"
ServicePath="~/ManagerLicencjiService.asmx" ServiceMethod="GetKontrahenci"
UseContextKey="true" ContextKey='<%# Bind("Lic_PosiadaczLicencjiID") %>'>
</asp:CascadingDropDown>
</EditItemTemplate>
</asp:FormView>
<asp:sqldatasource id="yourDataSource"
selectcommand="select Lic_PosiadaczLicencjiID FROM yourdatabase"
UpdateCommand="Update yourdatabase set Lic_PosiadaczLicencjiID = #newvalue WHERE Lic_PosiadaczLicencjiID = #Lic_PosiadaczLicencjiID"
connectionstring="<%$ ConnectionStrings:yourConnectionString %>"
runat="server"
onupdating="yourDataSource_Updating">
<UpdateParameters>
<asp:Parameter Name="newvalue" DbType="String" />
</UpdateParameters>
</asp:sqldatasource>
code behind:
protected void yourDataSource_Updating(object sender, SqlDataSourceCommandEventArgs e)
{
e.Command.Parameters["#newvalue"].Value = ((DropDownList)fv1.FindControl("Lic_PosiadaczLicencjiIDDropDownList")).SelectedValue;
}
and in your web service where you are getting your data from you need to add the context key to the signature exactly as shown as it is case sensitive. You then check your returned values for the selected value and set selected = true. If you want selected value instead of selected text then check for x.value instead of x.name.
[WebMethod]
public CascadingDropDownNameValue[] GetKontrahenci(string knownCategoryValues, string category, string contextKey)
{
CascadingDropDownNameValue[] results = getdata();
CascadingDropDownNameValue selectedVal = (from x in results where x.name == contextKey select x).FirstOrDefault();
if (selectedVal != null)
selectedVal.isDefaultValue = true;
return results;
}
Hope this helps!