I have a routine that i call clientside using Javascript. For this reason, it has to be a webmethod hence it must be 'shared' (static in C#)
<System.Web.Services.WebMethod()> _
Public Shared Sub LoadBewerkIndirecteKosten(_team As String, _year As Integer)
Try
' dconnection = DatabaseConnection.Instance
Dim con As New Connection
Dim sql As String = ""
sql = String.Format(" exec CSSSR_FEZ_Get_BewerkIndirecteKosten '{0}', {1} ", _team, _year)
Dim dt As DataTable ' = New DataTable
Dim ds As DataSet = con.QueryUnsecure(sql, Nothing, EDLQueryOptions.DataSet)
dt = ds.Tables(0)
SSR_IndirecteKosten.gvBewerkIndirecteKosten.DataSource = dt
gvBewerkIndirecteKosten.DataBind()
Catch ex As Exception
log.Fatal(String.Format("Error in: {0}: {1}", "LoadBewerkIndirecteKosten", ex.Message))
End Try
End Sub
In the javascript (which is in my aspx), i call this function like this:
PageMethods.LoadBewerkIndirecteKosten('FEZ', 2014, OnSucceeded, OnFailed);
Normally this construction works perfectly, as long is a don't call sreen components, but in this case, i run a stored procedure, fill a datatable and want to databind it to the gridview.
Does anyone know how?? Thanks in advance!!
Related
I am new to programming and get the chance to work and maintain in another developers project.
The project is built with ASP.Net Vb.Net and SQl Server.
I am trying to select the primary key ID (which is actually a GUID) from a table.
SQID = Core.DB.GetString("SELECT id FROM SQC WHERE sid = " & sid)
In the Table SQC the primary key is id which is guid and the sid is also guid which is primary key to another table.
my previous developer developed the code to select string variable GetString function where GetString is
Shared Function GetString(ByVal selectQueryText As String, ByVal ParamArray params As SqlParameter()) As String
Dim dt As DataTable = Nothing
Try
dt = GetData(selectQueryText, CommandType.Text, params)
If dt.Rows.Count = 0 Then
Return ""
Else
If TypeOf dt.Rows(0)(0) Is DBNull Then
Return ""
Else
Return CStr(dt.Rows(0)(0))
End If
End If
Finally
If dt IsNot Nothing Then dt.Dispose()
End Try
End Function
When I debug the code my process enters into GetString Function and from Get String it goes to GetData function
Shared Function GetData(ByVal selectCommandText As String, ByVal selectCommandType As CommandType, ByVal ParamArray params As SqlParameter()) As DataTable
Dim conn As SqlConnection = Nothing
Try
conn = GetOpenSqlConnection()
Return GetData(conn, selectCommandText, selectCommandType, params)
Finally
If conn IsNot Nothing Then conn.Dispose()
End Try
End Function
Shared Function GetData(ByVal conn As SqlConnection, ByVal selectCommandText As String, ByVal selectCommandType As CommandType, ByVal ParamArray params As SqlParameter()) As DataTable
If conn Is Nothing Then Return GetData(selectCommandText, selectCommandType, params)
Dim sa As SqlDataAdapter = Nothing
Try
sa = New SqlDataAdapter(selectCommandText, conn)
sa.SelectCommand.CommandType = selectCommandType
Dim dt As New DataTable
Try
For Each param As SqlParameter In params
sa.SelectCommand.Parameters.Add(param)
Next
sa.Fill(dt)
Return dt
Catch ex As Exception
dt.Dispose()
Throw ex
End Try
Finally
If sa IsNot Nothing Then sa.Dispose()
End Try
End Function
In the Try Catch area of exeption handling the code breaks and throws the exception error. It saying Incorrect syntax near 'a379'. which is first the part of sid (GUID). I mean the sid value is 9417A379-6371-432F-9DA5-BCFC46DD95A1
I am not sure how to handle this. I want to select the id from from SQC table and store it in a variable.
I am looking for your advice and suggestion. As I am new in the programming world please also point me my mistakes.
Thanks
It looks like your issue could be fixed like so:
SQID = Core.DB.GetString("SELECT id FROM SQC WHERE sid = '" & sid & "'")
But you should be aware that this style of code is open to SQL injection and you may want to look at ways of parameterising your queries (i.e. don't take what's in this project as good practice).
When I consuming a webservice (asmx) the first time and return a DataTable to my aspx project, everything is ok. However, if I consume the webservice again on that same aspx the previous DataTable object is completely empty. Why is that?
This is my webservice method:
<WebMethod()> _
public Function QueryGeneralText() As DataTable
ds.Reset()
com.Parameters.Clear()
com.CommandText = queryString
com.CommandType = select booksID from Books"
com.Connection = con
conectarBD()
da = New SqlDataAdapter(com)
da.Fill(ds)
con.Close()
Return ds.Tables(0)
End Function
On the aspx.vb section:
Public Sub CreateDatatable()
Dim example1 As DataTable = ws.QueryGeneralText() ' RETURNS DATA
Dim example2 As DataTable = ws.QueryGeneralText() ' RETURNS DATA, BUT EXAMPLE ITS EMPTY
End Sub
It looks like you are using a global ds object - so you function is working on the same resultset.
First time you execute the function it works, nobody else has any results in ds, but next time you already have results there but now your reset drops the results.
If this is true, you might fix it by creating the ds inside the function instead if possible.
I'm having a problem populating a child gridview using a function I define. I keep getting the error "Object reference not set to an instance of an object". What am I doing wrong? Am I using the FindControl function incorrectly? It doesn't seem to find the child gridview.
Sub RecordsByZip()
Dim DBConn As New SqlConnection(Application("DBConn"))
Dim gv1 As GridView
gv1 = grdTotal
Dim gv2 As GridView
gv2 = DirectCast(gv1.FindControl("grdChild"), GridView)
Dim ZipCode = lbZip.SelectedItem
For Each ZipCode In lbZip.Items
If ZipCode.Selected = True Then
Dim cmdZip As SqlCommand = New SqlCommand("spPICAInsertTotals2", DBConn)
cmdZip.CommandType = CommandType.StoredProcedure
strZip = ZipCode.Text
strUser = Session("User")
Dim Zip As New SqlParameter("#Zip", SqlDbType.VarChar)
Zip.Value = strZip
cmdZip.Parameters.Add(Zip)
Dim UserID As New SqlParameter("#UserID", SqlDbType.Int)
UserID.Value = strUser
cmdZip.Parameters.Add(UserID)
DBConn.Open()
gv1.DataSource = cmdZip.ExecuteReader
gv1.DataBind()
gv1.Visible = True
DBConn.Close()
End If
Next
btnExport.Visible = True
lblmsg.Visible = False
' Dim DBConn = New SqlConnection(Application("DBConn"))
Dim cmdCounty As SqlCommand = New SqlCommand("spPICAInsertTotals", DBConn)
cmdCounty.CommandType = CommandType.StoredProcedure
'Dim gv As GridView = TryCast(e.Row.FindControl("grdChild"), GridView)
strUser = Session("User")
Dim UserID2 As New SqlParameter("#UserID", SqlDbType.Int)
UserID2.Value = strUser
cmdCounty.Parameters.Add(UserID2)
DBConn.Open()
gv2.DataSource = cmdCounty.ExecuteReader
gv2.DataBind()
gv2.Visible = True
DBConn.Close()
btnExport.Visible = True
lblmsg.Visible = False
lblInstructions.Visible = False
End Sub
First of all . . .
Just as a disclaimer, I normally use repeater controls instead of gridview controls.
But this may help you . . .
I can tell you that with repeater controls, if you want to find a nested repeater then you must look for them inside the item of the parent repeater to which they belong. Essentially, what you are trying to do with the code above, is find grdChild when there might actually be several grdChild (it is a nested gridview, after all). I'd be willing to bet this is where you're object reference error is occurring.
In other words, if you want to find the nested repeater with the ID nestedRepeater, and you know it is located in the first item of your main repeater (which in this case I've assigned to the myRepeater variable), you can do this:
Dim myItem as RepeaterItem = myRepeater.Items(0)
Dim Rep2 as Repeater = myItem.FindControl("nestedRepeater")
Using SqlDataAdapter and a DataSet (recommended)
Dim sa As New SqlDataAdapter(cmdCounty) 'Initialize the SqlDataAdapter and assign the SqlCommand object to it.
Dim ds As New DataSet() 'Initialize the DataSet (we will bind this to the gridview)
Try 'The Try/Catch statements help you to handle errors.
cmdCounty.Connection.Open() 'Open the connection to the database.
sa.Fill(ds) 'This statement uses the SqlDataAdapter to easily execute the SqlCommand (using the query specified in the SqlCommand object) and . . .
'. . .use that data to fill our dataset.
cmdCounty.Connection.Close() 'These statement close the connection and dispose of the SqlCommand object. Note: You may only need the dispose command.
cmdCounty.Dispose()
Catch ex As Exception
'Catch your error here.
cmdCounty.Connection.Close()
cmdCounty.Dispose()
End Try
gv2.DataSource = ds 'Set the datasource for your GridView control.
gv2.DataBind() 'Bind the data.
Using SqlDataReader and a DataTable
According to your comment, you're code is breaking when you assign the gridview to the cmd.ExecuteReader.
You will need to access your data using a method like this:
Dim rdr as SqlDataReader = cmdCounty.ExecuteReader() 'Declare the SqlDataReader and set it to handle your SqlCommand.
Dim dt as New DataTable 'Initialize a new DataTable. This is where we will place the information we read using the SqlDataReader.
'Make sure you add the columns...
dt.Columns.Add("firstColumnName") 'Create a column for each field you will be retrieving data from.
dt.Columns.Add("secondColumnName")
Dim r as DataRow 'Declare the variable r as a DataRow.
'You may want to insert the line "If rdr.HasRows Then" to check if any data was pulled before attempting to read it.
While rdr.Read() 'Loop through each row in the reader.
r = dt.NewRow() 'Set r to equal a new DataTable in the DataTable we created. Note: This does not actually add the row to the table.
r("firstColumnName") = rdr("firstColumnName") 'Set the values of each column in the current DataRow to equal their corresponding data read from SQL.
r("secondColumnName") = rdr("secondColumnName")
dt.Rows.Add(r) 'Add the DataRow r to the DataTable.
End While 'Loop back until there are no more rows.
gv2.DataSource = dt
gv2.DataBind()
Both of these examples assume you have already created your SqlCommand object and have assigned a working SQL query string and Connection object to it.
Hello stack overflow residents! this is my first post and i'm hoping to receive some help.
I've searched but because I'm still very new, i was not able to full find/understand my answer.
I keep encountering this error:
Message: Conversion from string "" to type 'Date' is not valid. File:
~/reports/pendingshipments.aspx Function: btnExportXls_Click Stack
Trace: at
Microsoft.VisualBasic.CompilerServices.Conversions.ToDate(String
Value) at reports_default.btnExportXls_Click(Object sender, EventArgs
e) in C:\Users\jet.jones\Documents\ERIRoot\ERITitan\ERITitan.ssa\Web
Application\reports\pendingshipments.aspx.vb:line 75
Here is my code:
on App_code
**Public Function Reports_PendingShipments(ByVal intClientID As Integer, ByVal strMinDate As Date?, ByVal strMaxDate As Date?, ByVal xmlSiteID As String) As DataTable
'=================================================================================
' Author: Jet Jones
' Create date: 2013.05.28
' Description: Returns a data table with pending shipments for the sites specified
'=================================================================================
Dim objConn As New SqlConnection(System.Configuration.ConfigurationManager.ConnectionStrings("Titan").ToString)
Dim cmdGet As New SqlCommand("spReports_PendingShipments", objConn)
Dim parClientID As New SqlParameter("#ClientID", SqlDbType.Int)
Dim parMinDate As New SqlParameter("#MaxDate", IIf(Not strMinDate.HasValue, DBNull.Value, strMinDate))
Dim parMaxDate As New SqlParameter("#MaxDate", IIf(Not strMaxDate.HasValue, DBNull.Value, strMaxDate))
Dim parSiteID As New SqlParameter("#Sites", SqlDbType.Xml)
Dim objAdapter As New SqlDataAdapter(cmdGet)
Dim objTable As New DataTable
parClientID.Value = intClientID
parMinDate.Value = strMinDate
parMaxDate.Value = strMaxDate
parSiteID.Value = xmlSiteID
'set up the command object
cmdGet.Connection = objConn
cmdGet.CommandType = CommandType.StoredProcedure
'add the parameters
cmdGet.Parameters.Add(parClientID)
cmdGet.Parameters.Add(parMinDate)
cmdGet.Parameters.Add(parMaxDate)
cmdGet.Parameters.Add(parSiteID)
'open the connection
objConn.Open()
'execute the query and fill the data table
objAdapter.Fill(objTable)
'return the data table
Reports_PendingShipments = objTable
'clean up
objConn.Close()
objConn = Nothing
End Function**
my aspx.vb page calls this function this way (Get the values from the query):
objTable = Reports_PendingShipments(ucClientSearch.Value,
txtMinDate.Text, txtMaxDate.Text, strSites)
I'm passing the variable strSites because the website permissions allow for users to have access to one or more site locations, and if a report is run and the user selects "All Sites" from the dropdown, I only want to send the sites they have permissions to via XML.
If I'm missing any information please let me know!
anyone's prompt response is so greatly appreciated.
The problem is that your code is expecting empty dates to be NULL, it doesn't check for empty strings. You need something like this:
if len(strMinDate)=0 then
strMinDate = "01/01/1980"
end
Not sure what you want to default the minimum date to, but you need to add code similar to the IF statement above
Be sure to add this code prior to using the variable a few lines later...
First of all, you adding MaxDate parameter twice:
Dim parMinDate As New SqlParameter("#MaxDate", IIf(Not strMinDate.HasValue, DBNull.Value, strMinDate))
Dim parMaxDate As New SqlParameter("#MaxDate", IIf(Not strMaxDate.HasValue, DBNull.Value, strMaxDate))
And moreover, then you setting parameters values wuthout check for HasValue:
parMinDate.Value = strMinDate
parMaxDate.Value = strMaxDate
Remove these lines and fix min date parameter name
I have the below mentioned code in a seperate class file for establishing connection and carry out DB transactions. I have an issue where multiple connections being opened which sometime exceed the connection pool. When I stepped through the code I found that there are codes which call ConnectDB() in a loop without calling DisconnectDB(). But I expected that the condition OraConn.State = ConnectionState.Closed should handle the situation. Somehow the condition is always satisfied hence openning another set of connection. Can you suggest where am I going wrong and also what best practice can be adopted here?
Public Class Connection
Dim Str_conn As String = "Data Source=...; User=...; password=...; Min Pool Size=10; Max Pool Size=500;"
Public OraConn As OracleConnection
Dim cmd As OracleCommand
Dim dr As OracleDataReader
Dim data_adapt As OracleDataAdapter
Dim dt As DataTable
Dim ds As DataSet
Public Sub ConnectDB()
OraConn = New OracleConnection(Str_conn)
If OraConn.State = ConnectionState.Closed Then
OraConn.Open()
End If
End Sub
Public Sub DisconnectDB()
If OraConn.State = ConnectionState.Open Then
OraConn.Close()
End If
End Sub
Public Function get_dataset(ByVal query As String, ByRef ds As DataSet) As DataSet
data_adapt = New OracleDataAdapter(query, OraConn)
data_adapt.Fill(ds)
Return ds
End Function
Public Function get_datareader(ByVal query As String) As OracleDataReader
cmd = New OracleCommand(query, OraConn)
dr = cmd.ExecuteReader()
Return dr
End Function
Public Sub UpdateDB(ByVal query As String)
cmd = New OracleCommand(query, OraConn)
cmd.ExecuteNonQuery()
cmd.Dispose()
End Sub
The class is refered in other classes or directly in the aspx.vb pages like this.
Public Function InsertData(ByVal var1 As String, ByVal var2 As String) As Integer
conn.ConnectDB()
Dim qryInsert As String
qryInsert = " INSERT INTO TABLE VALUES ('" & var1 & "', "
qryInsert = qryInsert & var2 & "')"
Try
conn.UpdateDB(qryInsert)
Catch ex As OracleException
If ex.Code = 1 Then
updData(var1, var2)
ElseIf ex.Code = 2091 Then
msgprompt("Duplicate Unique Key!", "Warning")
End If
Finally
conn.DisconnectDB()
End Try
Return count
End Function
The connection is again opened in function updData(). While I understand that it has to be closed correctly but keeping tab on every developer is not possible. Hence I want to control it directly from the connection class by using the same connection but the condition If OraConn.State = ConnectionState.Closed is not helping.
UPDATE
I have put the code in UpdateDB under a Using block and removed call to ConnectDB and DisconnectDB from function like InsertData(...). It seems that the issue has been resolved. But I would like to know in case of exception will the connection remain open? and also OraConn is a public variable defined outside Using block so will it be disposed of by the GC?
Public Sub UpdateDB(ByVal query As String)
Using OraConn = New OracleConnection(Str_conn)
cmd = New OracleCommand(query, OraConn)
Try
OraConn.Open()
cmd.ExecuteNonQuery()
Catch ex As Exception
Throw
Finally
cmd.Dispose()
End Try
End Using
End Sub
You must close all the connections as soon as you are done with it, no matter what.
Suggestion:
The best practice for closing the connection is to do it in finally block. So that even if there is any error, catch it (log it if required) in catch block, and then connection will get close in finally block.
UPDATE
You can put one private static counter in your Connection class. When ever ConnectDB() is called you increment this counter and decrement it in every DisconnectDB(). Now in ConnectDB() you check the value of counter, if it exceeds a minimum threshold you throw error, by doing this way; you can come to know idle connection present in your code and refactor it. On production keep this threshold value high or ignore it in code.