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The XML Files: Object Graphs, XPath, String Comparisons, and More

Posted By:      Posted Date: August 21, 2010    Points: 0   Category :ASP.Net

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The XML Files: Introducing XPath 2.0


Over two years ago in one of the first installments of this column, I wrote about XPath version 1. 0 (see The XML Files: Addressing Infosets with XPath for a quick review). As stated in the original specification: "XPath is a language for addressing parts of an XML document.

Aaron Skonnard

MSDN Magazine January 2003

Cannot send List inside of Dictionary

List<string> receivers = new List<string>(); foreach (object item in listBoxControl1.SelectedItems) receivers.Add((string)item); Dictionary<string, object> inArgs = new Dictionary<string, object>(); inArgs.Add("Receivers", receivers); inArgs.Add("Sender", client.name); inArgs.Add("Message", memoEdit2.Text); inArgs.Add("IsGuaranteedDelivery", true); inArgs.Add("DataType", TransmitToClientDataType.ChatMessage); if (service != null) service.AddTask("orion_send", inArgs); There is an error with serialization at last string because List<string> object. I tryed to send List<T> object via WCF, it's succesfull. But why there are problems with List<T> included to Dictionary?

how to find multiline string literals (@"bla") in .cs files (C# sourses)

Hello, My app searches a key word over .CS file (C# sourse) and I want to exlude all string literals because of possability of appearance of key word within this string which is unwanted. I've already composed a regex for common strings - like this - string s = "bla \"bla\" bla" ; This is highlighted correctly by ((?<!(\\|@))".*?"(?<!\\")) But I can't fix up the case with multiline strings. For instance - string s = @"bla ""bla"" bla" ; or string s = @" bla ""bla"" bla" ; In such type of strings there is a rule - within strings can be quotes but only if they are doubled. These are correct examples - @"bla """"""""bla """""" bla" @""" bla """"bla bla" @""""" bla"" bla bla""" These are incorrect - @"" bla "" bla bla"" @"bla """ bla bla" I have some clues - I know how to catch even quantity of quotes - by this regex - ((?<!")("")*(?!")) how to catch odd quantity - ((?<!")"("")*(?!")) how to catch strings which have even quantity of quotes, ex

Weird Issue with the MOSS Search : FileExtension metadata object type instead of string

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Unable to cast object of type 'System.Guid' to type 'System.String'.

protected void Button1_Click(object sender, EventArgs e) { using (BurnbetDataContext dc = new BurnbetDataContext()) { var q = (from c in dc.GetTable<tbl_Payment>() where c.ID == 5 select c).Single<tbl_Payment>(); dc.GetTable<tbl_Payment>().DeleteOnSubmit(q); dc.SubmitChanges(); } } }System.InvalidCastException was unhandled by user code  Message=Unable to cast object of type 'System.Guid' to type 'System.String'.  Source=System.Data.Linq  StackTrace:       at System.Data.Linq.SqlClient.SqlProvider.Execute(Expression query, QueryInfo queryInfo, IObjectReaderFactory factory, Object[] parentArgs, Object[] userArgs, ICompiledSubQuery[] subQueries, Object lastResult)       at System.Data.Linq.SqlClient.SqlProvider.ExecuteAll(Expression query, QueryInfo[] queryInfos, IObjectReaderFactory factory, Object[] userArguments, ICompiledSubQuery[] subQueries)       at System.Data.Linq.SqlClient.SqlProvider.System.Data.Linq.Provider.IProvider.Execute(Expression query)       at System.Data.Linq.DataQuery`1.System.Linq.IQueryProvider.Execute[S](Expression expression)&nb

converting a rdr object to a string


I inherited some code and I need to change a line so that instead of testing to see if the value in a table column is not null, it also tests to see if the value is not empty.

The existing line is:

if (rdr["InnLinkURL"] != null)

"InnLinkURL" is the name of the column being tested.

I thought a solution could be something like:

if (String.IsNullOrEmpty(InnLinkURL) == true)

Not sure how to convert the object to a string, though.

public static string ToString(
 object value

If someone could show me the proper syntax I'd be grateful.

As an alternative, I tried this also but it doesn't seem to work (no errors, just doesn't return true)

if ((rdr["InnLinkURL"] != null) && (rdr["InnLinkURL"] != ""));

Unable to cast object of type 'System.DBNull' to type 'System.String'.


 I saw lots of post about this issue. but haven't got good solution for that yet. Basically, what I did is that: I have a table in SQL database and some of data fields allow null. I built Objectdatasource through dataset. When I built update page using dataset. It generate the following error before showing the update page correctly. It seems I have issue to retrieve the null value from the database through using objectdatasource through dataset. Any suggestions?




Error attached below:

Unable to cast object of type 'System.DBNull' to type 'System.String'.

Description: An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error and where it originated in the code.

Exception Details: System.InvalidCastException: Unable to cast object of type 'System.DBNull' to type 'System.String'.

Source Error:

Line 1178:            get {
Line 1179:                try {
Line 1180:                    return ((string)(this[this.tablemember.CurrentCityStateColumn]));
Line 1181:                

Keep updating Session object with a new List c#


I have a Session object

Session["MyListObjects"] = null;

When a user hits a button I want to creat a List<string> object and add to session object.

Let's say if user hits the button 10 times, I would get 10 List<string> objects and
add to Session["MyListObjects"] and

Finally I want to read all the List<string> objects from the session object.

Please let me know how to do that.

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Can anyone help me.




Object of type 'System.Int32' cannot be converted to type 'System.String


When i'm trying to update a table using dynamic data, i'm getting the following error. I was trying to google the solution for the whole day, but it didnt work. I tried to declare the type of parameters like this

<asp:LinqDataSource ID="DetailsDataSource" runat="server" EnableUpdate="true"
                onupdating="DetailsDataSource_Updating" > <UpdateParameters><asp:Parameter Name="PK_ID" Type="Int32" /><asp:Parameter Name="id" Type="Int32" />
                <asp:Parameter Name="c_titulu" Type="Int32" />
                <asp:Parameter Name="perio" Type="Int32" />

Convert XML to object returns null due to unwanted string


Hello All,

I am facing very odd problem, when I check my xml string than in header it contain one unwanted string square [], like below, due to that casting to object is not happening. Due to that it returns null

[]<?xml version="1.0"?>

But when I remove [] and convert to object then it works fine. Any one has any idea.

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