Why SqlDataReader Class object is not created by "new" Operator.
Is it not possible to create the object like below
SqlDataReader dr=new SqlDataReader();
dr=cmd.ExecuteReader();
Why the constructor of the SqlDataReader class is internal?
When I am using SqlDataReader class on that time without creating instance of the SqlDataReader Class I m using Command.ExecuteReader() Method. Why We not create the object of the SqlDataReader Class by using " new " Operator.We use like below:
SqlDataReader dr=cmd.ExecuteReader();
Why not we use this class like below:
SqlDataReader dr=new SqlDataReader();
dr=cmd.ExecuteReader();
I am interested to know what happens with unused properties of a class when an object is instantiated?
Are there performance hits for having additional unused properties? What about complex properties that are accessing the database, but I'm not using them, are they still being loaded?
I am trying to run a stored proc from this function. When I run it thorugh the debugger I can see that myReader.HasRows = true and myReader.FieldCount =14.
But the control does not go in the loop while (myReader.Read()) where I am trying to read Version field returned by the stored proc.
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I'm trying to convert some code from VB to C# on a site i'm working on and can't seem to get the arraylist to function properly.
Here is what we currently have in the codebehind:
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Which we then call from the page using:
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I want to convert this to C# as the rest of the code on the new site is in C# and I'm having problems with the ArrayList. I've got the other parts of the code all converted fine it's just the GetContent Function that isn't working right. Here's what I have:
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I got an error on the "objSDR.Item" part of the code saying "SqlDataReader doesn't have definition for Item" and so if I changed this to the code above. Only problem now is I can't call this from the page using the code below as there is no "Item" in the GetContent Function any more
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In SQL Server 2008 bit is like boolean (true/false), but I tried to read the bit value (0 or 1) and got error. How can I read it?
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how to read data from the sqlDataReader .
sqlDataReader sdr = sql_comm.executeDataReader();
if(sdr.hasRows)
{
while(sdr.read)
i=0
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My question is how do i use SqlDataReader to read the last row added to a table getting the contents of a column and storing it as a c# varaible
When using the DataTable.Load(SQLDataReader) method, if the datatable is a property of a class, the set method is not called to populate the object. For example...
MySQLDataReader = command.ExecuteReader();
if (MySQLDataReader.HasRows)
myObjDataTable.Load(MySQLDataReader); -- The result of this will be 0 rows returned. The "Set" method of the object is never called.
I have a vb class that reads a single row of data from an SQL view. I want to add a property to it that will expose the value of a new bit field. But whatever I do my class always returns the value "false".What am I doing wrong?
Public ReadOnly Property IsPublished() As Boolean
Get
Return valPublished
End Get
End Property
Here's the relevant line from my datareader: Me.valPublished = Convert.ToBoolean(theObjectReader("Authorised"))Authorised is my bit field. I have tried it with and without the "ConvertToBoolean" statement.When I response write the value of the property for rows where this field is true, it always shows false.
I have several methods where I return a SqlDataReader to populate Gridviews, Listview, etc. I get random "Timeout expired" errors regarding connection pooling, so I decided to add using{} to my methods. The lack of using is a carry over from my more beginner days.Below I included the before and after code. The after code always gives me the "Invalid attempt to call FieldCount when reader is closed" error. I have tried various combination of using{}, but ALL result in the same error.What am I doing wrong? Also, from the code below what is the best way to structure this code to ensure no connection leakage?Before:
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After:
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I know it is recommended to use a using statement with a sqldatareader, but I was wondering if it is necessary when you are setting the datasource of a control to a datasource directly. in some places in my code I do this.
using (SqlDataReader reader = getReader())
{
while (reader.Read())
{
// do stuff with data
}
}
when binding to a control I do this.
ddlCustomer.DataSource = getReader(); // get Reader returns a sqldataReader
ddlCustomer.DataBind();
In the second case, do I need to use a using statement. Do i have to first declare an SqlDataReader in a using statement, then set the DataSource to that object. Seems like more clutter in the code, so i was hoping binding to the SqlDataReader disploses of the SqlDataReader.
I have a link button on my page :
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And here is it's click event :
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So why does line 181 have to be instantiated ?
I am really having a hard time trying to write something from scratch I created a 'Person' Class.Public Class Person
Private _FirstName As String = ""
Private _LastName As String = ""
Private _Age As Integer = 0
Public Sub New(ByVal FirstName As String, ByVal LastName As String, ByVal Age As Integer)
FirstName = FirstName
_LastName = LastName
_Age = Age
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how to convert sqldatareader to List
View 2 Repliesi am using,Asp.net(vb),database sql server 2005, i want to use sysdsn DSN for database connection,so please Guide me how do i use DSN using web.config and class(we have sqlhelper type our own DBclass to set connectionstring for whole applicatoin. which get connection string from web.config),
Now,how do i use/set dsn in this type of scenario.
I need to be able to Page in my Datalist. As you can see from the code below I'm using a SqlDataReader to populate my Datalist.
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When I used the (way #1) below I could retrieve search result from my DB
Way #1:
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But When I use( way#2) "separating my code to Presentation layer and data access layer ( using SQL HELPER CLASS )"
Way # 2
Presentation layer: protected void btn_Search_Advance_Click(object sender, EventArgs e)
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data access layer:
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I keep getting this error: Procedure or function 'SP_Search' expects parameter '@SEARCHTYPE', which was not supplied.
I have a webform whose ObjectDataSource reads an xml file to populate a GridView in the .aspx page. I have to hard code the file path in the .cs file defining the ObjectDataSource classes. I want to be able to use a portion of the query string to indicate which file to select, but, normal methods, like Server.MapPath and Http.Request.Current don't work in the class page. how I can pass values from the SelectParameters configured in the ObjectDataSource down to the ObjectDataSource method? Here is my Class code:
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The filePath variable is what I want to be able to alter based on my query string.
string connectionString = (string)
ConfigurationSettings.AppSettings["ConnectionString"];
SqlConnection connection = new SqlConnection(connectionString);
SqlCommand command = new SqlCommand("INSERT_PERSON",connection);
command.CommandType = CommandType.StoredProcedure;
command.Parameters.Add(new SqlParameter("@Name",SqlDbType.NVarChar,50));
command.Parameters["@Name"].Value = txtName.Text;
command.Parameters.Add(new SqlParameter("@Age",SqlDbType.NVarChar,10));
command.Parameters["@Age"].Value = txtAge.Text;
connection.Open();
command.ExecuteNonQuery();
connection.Close();
Above is my code.
I has more than 100 methods like this, so every time i'm opening the connection and close it, this will take too much of time, what i think is instead of this i would like to create the class for Connection open, that class will check whether the connection is closed or Broken then Open it(like SqlHelper.cs) so without big change on my methods, how to create that class and how to access that class from my methods.
i've created a dataset, and created inside it a datatable and its table adapter.
when i try to reference the table adapter in a .cs class i get an error message that i'm missing some namespace:
Compiler Error Message: CS0246: The type or namespace name 'DataSet1TableAdapters' could not be found (are you missing a using directive or an assembly reference?)
Not sure if I'm posting in the right place so please forgive meI have an ASP.NET C# application that connects to either a SQL Server or MySQL database depending on some value that is set in my project config. The issue I'm trying to avoid is handling the connections and queries separately. Ideally I would want to use a DB Wrapper class that can handle both SQL Server and MySQL.
View 8 RepliesI have a MVC 2 project I'm trying to deploy to a QA server, and I'm having fits. I get a YSOD with the error starting as:
[InvalidOperationException: An error occurred when trying to create a controller of type 'DSC.Web.Controllers.HomeController'. Make sure that the controller has a parameterless public constructor.]
I've installed Visual Studio on the server, and the application runs without issue from Visual Studio. I've also checked the HomeController and it does have a parameterless public constructor. What could be causing this issue?
The server specs:Windows 7 Enterprise 64-bit
IIS Version 7.5.7600.16385
When using SqlDataReader.NextResult for 2 queries I am trying to I check if the second query returns any rows, but whether it has any rows or not the repeater2 is never hidden/false . I am doing something like this:
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I am developing a message pool means like a Facebook when we click on above message icon all message show in list .then click on the sender name all message show that person. For
That kind of message poll am developed two pages one page is sender and the other one is receiver .when I send message from sender page it will be saved into data base and show into other pages text box.
Now problem is that the receiver pages cannot show all messages .it will show one first message which are saved into database.
I want it will show all messages which are sending from sender page. below my all code.
WebForm1.aspx.css
using System;
using System.Collections.Generic;
using System.Linq;
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