I am writing a simple XML web service and want to return raw XML. I am doing this by creating a string literal that represents the XML. My data source is a SqlDataReader object that contains the results of a stored proc call. The way I am doing it right now is by using a while loop and reading values from the item property like so :
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My question is: Using SqlDataReader. Suppose I have SQLdr instantiated. I can get data from some column using:
SQLdr("some_column")
Now if I know that column "Value" has a some value, I can get it this way:
eg. 1
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My motivation is to have easy-on-the-eyes code (not too dense on the page with long expressions). I have one application I'm studying where there are hundreds of expressions like eg. 1. If I could get the ordinal values at the start, I could use expressions like eg. 2 instead. As a bonus, I would eliminate redundant calls to GetOrdinal for queries that return thousands of rows.
however, this is clearly erroneous if the ordinal values might change between calls to SQLdr.Read().
I would like to iterate through a dataset and obtain values of each column in a row
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Does anyone know a Good tutorial on how to use The SqlDataReader in VB.Net ?
View 4 RepliesI'm not sure about this code. What I wanted to do is to count the number of records in the table that I selected and then add a value of 1 to it to generate a transaction number.
I'm not sure on how to count the number of rows in the reader. So far, this is my code.
Dim intTransaction As Integer = 0
Try
con.Open()
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How can I reuse(reopen) same Datareader after calling Close() ??
View 1 RepliesMy SQL query shows 8 rows when executed but the following code only shows 7. Apparently, it�s missing the first row.
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Dim temp as String = Nothing
Dim r As SqlDataReader = objCmd.ExecuteReader()
If r.Read() = True Then
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Can i use SQLDataReader instead of a Recordset. I want to achieve the following result in an SQLDataReader.
Dim dbConn As New ADODB.Connection
Dim rs As New ADODB.Recordset
Dim sqlstr As String = "SELECT Name,Status FROM table1 WHERE id=" +
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can i replace recordset with SQLDataReader and if I can can you please show me the changes in code.
I would like to pass two values to a stored procedure. I am using a sqlreader to export data to an excel sheet. I need the user to be able to select a range, rather that the whole sql table. the code works fine without adding parameters, but I need the user to be able to select a range, rather that the whole table.
Dim data As String = ""
sqlCon.Open()
sqlCmd = New SqlCommand(strSQL, sqlCon)
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I have an XML file, with a rather large structure. I'm pulling several entities out of it throughout several systems, and its dynamically updated once a day. I'm using a Linq Query that is exhibiting odd behavior, its only returning if the first entry in the site tag matches the search-pattern. If its number 2 or 3, it fails to return anything. Why would this behave that way?
The following function written in VB handles pulling the data
Public Function xmlSchoolListBySite() As IEnumerable
Dim doc As XDocument = loadXML()
Dim loadedPrograms As IEnumerable(Of XElement) = From c In doc.Descendants("Organization") _
Where c.Descendants("site").Value = MySite.Site.s_Url _ 'contains Result.RawURL.tostring() formatted
Select c.Element("Title")
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I am trying to write XML that looks like this. It works so far, but when I get to the <rooms> node I can only output one.
<house>
<id>1</id>
<rooms>Living</rooms>
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I have two arraylists that contains links in one and the root url in the other. Sometimes the lists dont equal in number and I would like to iterate through the links list and if it contains a matching root url add it to a third list but also avoid any duplicates. I tried this but am not getting consistent results.
For Each link As String In urls
For Each part As String In post
If part.Contains(link) Then
[code]....
Perhaps there is another way; basically the part in post is a link to a page and contains the root url( which is link in urls). After extracting all these I need to ensure the 2 lists match.
I am iterating through rows in a datagridview in the following manner
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Why are the column methods and properties not all available in this manner to set individual datagridview cells properties? The only options available for the variable,
I am returning one row from the database, and I want to convert the SQLDataReader to a string format, so I can pass it to my webservice.
Dim rdr As SqlDataReader = sqlcmd.ExecuteReader
If rdr.HasRows Then
rdr.Read()
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I'm building a custom calendar control that queries our database to display corporate events. Here is the situation, there is an EndDate value stored and on the dev system one of the events have a NULL value. No big deal since it's only a test system, but might as well check before trying to use it anyway on the safe side. I figured the following code would work:
While dr.Read()
corporateTable.Rows.Add(New Object() { _
Convert.ToDateTime(dr("EventBeginDate")) _
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The thing that really gets me is, at one point I had this:
, IIf(dr.IsDBNull(column), Convert.ToDateTime(dr("EventBeginDate")).AddDays(1), Convert.ToDateTime(dr("EventEndDate"))) _
Thinking that it should work because it should only evaluate the dr() if it's not NULL. However, it kept erroring out at the end because the value was in fact NULL.Why is it that even though I'm checking if it's NULL before using the value, it errors out at the part that doesn't get called unless it's not NULL? Does it have to do with the fact that I'm using the IIF() and it's evaluating the whole statement? Or, using the dr(), it evaluates at runtime?
I just want to verify something. I believe it is likely that if I apply the using command to a SqlDataReader, that it will both close the data reader and dispose of it. For example:
Using sdr As SqlDataReader = cm.ExecuteReader()
Dim someInt As Integer = sdr.GetInt32(0)
'other details and actions
End Using
Will that close the sdr SqlDataReader after it exits the Using code block. (I believe it will, but just want to verify.)
What would happen if you call Close() on a SqlConnection object before you call Close() on a SqlDataReader using that connection?
Actually, what I really want to know is whether or not the order in which you Close them matters. Does calling SqlConnection.Close() completely close the connection, or will it remain open if you do not call Close() on a SqlDataReader using that connection?
I don't think I really understand how connection closing works.
How do i get the number of columns in a sqlDataReader after executing sql statement ?
View 4 RepliesI`m bussy building a ORM for our applications.I don`t want to use all of microsoft data functions like ADO.NET and Datasets because i would like to understande the base and manipulate data by code. I also want to make it later work like building a database out of the code in stead of the other way around.
I have build a simple appliacation inside VB.NET with a dataset and ADO.NET Entity.. When loading 250.000 records into objects it takes about 4.5 second. I`m using datareader to load a record of a database into a object dynamicly. I started at 15 seconds,later 8 and nu 6.5 seconds for the total amount of records.I started with TmpObject.ColumnName = Reader ("ColumnName"), later i figured out Reader.GetValues(TmpObjectArray) in combination with TmpObject.ColumnName = TmpObjectArray(0) is faster. Now i tought if i can set the properties as pointer to a object array so the values are placed onto the object instead of on a different object before it could be faster.
' PropertyArray
Dim tPropertyArray()
As PropertyInfo = tProperties.Values.ToArray[code]......
I am a beginner in VB.Net. I have a table tblName; which consist of columns 'Name' and 'ID'. I want to populate the comboBox, where displaymember = 'Name' and ValueMember = 'ID'. In short, when a user selects a 'Name', return value should be the 'ID'. I can do it using DataAdapter. Another way of doing is; using a Listbox in parralel with the comboBox, which will be hidden, to save the 'ID' .
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I need to populate all the values of a specific column in each rows of my table from my database. The specific column that i need is the "position",I'm using sqldatareader here's my code. I know that I need to use looping statements and the items.add properties of the combobox but I dont know how will I do it..hope you help me here..
Private Sub cboPosition_Click(ByVal sender As Object, ByVal e As System.EventArgs) Handles cboPosition.Click
scmd = New SqlCommand("SELECT KPIPOSTCODE FROM KKPIPOSITION", sqlcon)
sqlcon.Open()
scmd.CommandType = CommandType.Text
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I am currently using a sql data reader (in vb.net) to extract an article object via a stored proc from a SQL Server 2008 database. Part of this object includes the two properties shown below:
theArticle.Truthfulness = ((myReader.GetInt32(myReader.GetOrdinal("Truthfulness"))))
theArticle.Relevance = ((myReader.GetInt32(myReader.GetOrdinal("Relevance"))))
My problem is that the Truthfulness and Relevance may return a null value and this is causing the function to fall over.I think I understand why. I am asking for an integer value (getin32) and because null is returned it fails.How do I accommodate the null value from the database so it does not fall over?
This is incredibly urgent, I need to present this application in 3 and a half hours.My application checks against a data source to see if a value exists in the database and changes values depending on whether or not the value in question was found.The problem is that I've run the sql query with the value in question in SSMS and no rows were returned, and yet, my DataReader says it has rows.[code]val will only be returned True if the NumberToCheck (in this example 3235553469) exists in the database.Having copied the value of NumberToCheck into SSMS and testing the query there, I can verify that the query does work as expected.No, I can't populate a DataSet because of the volume of information in the table (+/- 9.5m rows). Even with the 'WHERE' filter, the query is too heavy on resources and eventually ends in an OutOfMemory Exception which is why I went with a DataReader.
View 4 RepliesMy code where errors occurred:
strSQL = "select * from transactions where TransactionID='" + txtTransactionID.Text + "'"
ReaderQuery(strSQL)
While dr.Read
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The weird thing about this, is that when I first run it, I was able to Bind it to all the Textbox and thought everything went smoothly, but when I run it again without any changes in that code, that error suddenly appears... sometimes that error went to other dr.item(""
I have several label boxes on my design form that all share the naming convention lbl_#.text where # ranges from 1 to 60. I want to make a loop that iterates through each lbl_#.text adding some incremental value, let's say multiples of 2 for this question's theoretical purpose.Something such that the end result would amount to the following:
lbl_1.text = "2"
lbl_2.text = "4"
lbl_3.text = "6"
lbl_60.text = "120"
I'm not sure how to access each of these labels through the coding side, I only know how to explicitly mention each label and assign a value :/
I have a list like this
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How can I iterate the list with ForEach to get one string with the emails like this [URL]
If I have a complex structure which contains properties which are both simple and complex types, how can I iterate over all the properties of this structure and any child properties which are not simple types?
I have a complex type called file, which contains lots of string properties and some which are other complex types which contain similar structures, eventually the whole structure breaks down into strings.
At the moment my code looks like this:
Dim file As New File
Dim props() As PropertyInfo = file.GetType.GetProperties()
_propList = New CheckBoxList
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This works, but it is ugly and I am not at all happy with certain chunks, specifically the type comparisons to establish if this is a date, string, decimal or boolean which are the potential low level types which I want to get out.
In C# it would seem these type comparisons are easier, but i seem to have to create an instance of a given type to be able to use GetType to return its type.
Can somebody show me how to loop through days between two DateTimes in VB?
View 3 RepliesI have a structure "xyz" with 3 string objects in it. "foo" "bar" and "abc" I want to iterate through the structure and compare the names of the objects.
Structure xyz
dim foo as string
dim bar as string
dim abc as string
End Structure
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I have an asp program that needs to validate data for textboxes that are dynamically created and put into a placeholder. Each textbox has to have a value when the user hits the Save button. I have the following code:
Dim testCheck As Boolean = True
For Each txt As TextBox In pnlTests.Controls
If txt.Text = "" Then
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