I'm trying to debug an issue I didnt create and I'm getting the generic error "The given key was not present in the dictionary." Here is the code:
Dim myInfo As New Dictionary(Of Integer, String)
For i As Integer = 0 To Region.GetRegionCount - 1
myInfo.Add(i, Server.HtmlEncode(ContentItem.Properties("StoreInfoRegion" & i).Value.ToString))
Next
Session(SESSION_INFO) = myInfo
When I step thru it the error occurs on the call to "Add", I guess Im confused because it's adding a key not trying to access one.
Thanks!
You have a pretty big line of code, split it up into it's pieces and you might find where the problem is exactly.
Instead of
myInfo.Add(i, Server.HtmlEncode(ContentItem.Properties("StoreInfoRegion" & i).Value.ToString))
Have
Dim propertyValue As String
propertyValue = ContentItem.Properties("StoreInfoRegion" & i).Value.ToString
propertyValue = Server.HtmlEncode(propertyValue)
myInfo.Add(i, propertyValue)
With this change, I'm pretty sure that you will see the error on the 2nd line where you fetch the value of Properties. This mean you do not have a value for "StoreInfoRegion" & i
You could do
If ContentItem.Properties.ContainsKey("StoreInfoRegion" & i) Then
Dim propertyValue As String
propertyValue = ContentItem.Properties("StoreInfoRegion" & i).Value.ToString
propertyValue = Server.HtmlEncode(propertyValue)
myInfo.Add(i, propertyValue)
End If
But I think you should first understand why there are no value for that key first.
Related
I have an asp.net/vb.net web app that requires information to be put into a multiline text box. If the user hits enter while in the textbox it drops down to next line, and they can enter more data in. When it tries to go to the database it fails because of the way the data is represented. I need help with looping through the field and getting each value.
This is how the data is represented in the DataTable
0;0.123;0.234;0.345;...
I need each value between the ; character... so I was thinking something like this?
If dbRow.Item("PV").ToString.Contains(";") Then
For Each symbol As String In DBTable.Rows
'get data b/w the ';'
Next
End If
Any help would be greatly appreciated
Edit:
If dbRow.Item("PV").ToString.Contains(";") Then
For Each s As String In dbRow.Item("PV").ToString
Dim fields() As String = s.Split(";"c)
For Each value As String In fields
.Append("'" & CDbl(value) & "'," & "SysDate,1)")
DBCommand.CommandText = myInsertIntoProperty_DataStringBuilder.ToString
DBCommand.ExecuteNonQuery()
myInsertIntoPropertyStringBuilder = New StringBuilder
Next
Next
Else
.Append("'" & CDbl(dbRow.Item("PV")) & "'," & "SysDate,1)")
End If
You mean something like this?
Dim s As String In dbRow.Item("PV").ToString()
Dim fields() As String = s.Split(";"c)
For Each value As String In fields
' Do what you want with the value
Next
Then access each value with field(0), fields(1), etc. You can then convert it to the appropriate type, for example:
Dim value As Double = Double.Parse(fields(0), CultureInfo.InvariantCulture)
I have a query string which has more than one value being passed through it and I need to access the second passed value... I have this as of now:
If Request.QueryString("ANBOS") IsNot Nothing Then
Dim url As String = HttpContext.Current.Request.Url.AbsoluteUri
Dim index As Integer = url.IndexOf("-")
If index > 0 Then
url = url.Substring(0, index)
End If
DBTable = MaterialStuff.GetComponentsForMaterial(CInt(Request.QueryString(url)))
I'm attempting here to dumb everything after the first value I need, then go back and look at the query string where it's equal to ANBOS and get its value, but when I go get the value of it, the whole query string is still there, both values...
How do I make it so I just get the first value? Any help is greatly appreciated :)
Edit: Query String being passed through
Response.Redirect("Edit.aspx?ANBOS=" & CType(flxSearchResults.SelectedItem.Cells(1).Text, Integer) & "MaterialNumberToUpdate=" & NextMaterialID)
Your query string is being generated incorrectly
Response.Redirect("Edit.aspx?ANBOS=" & CType(flxSearchResults.SelectedItem.Cells(1).Text, Integer) & "MaterialNumberToUpdate=" & NextMaterialID)
should be..
Response.Redirect("Edit.aspx?ANBOS=" & CType(flxSearchResults.SelectedItem.Cells(1).Text, Integer) & "&MaterialNumberToUpdate=" & NextMaterialID)
This is because the query string uses ampersand signs (&) to separate key value pairs.
I have the follwoing code that performs a query and returns a result. However, I looked around and found some examples to take care of null values but I get an error: "Invalid attempt to read when no data is present." I also got the error: "Conversion from type 'DBNull' to type 'Decimal' is not valid."
Can someone help me out with this code to prevent null values from crashing my program?
Private Sub EFFICIENCY_STACKRANK_YTD(ByVal EMPLOYEE As String)
Dim queryString As String = "SELECT " & _
" (SELECT CAST(SUM(TARGET_SECONDS) AS DECIMAL)/ CAST(SUM(ROUTE_SECONDS) AS DECIMAL) FROM dbo.APE_BUSDRIVER_MAIN WITH(NOLOCK) WHERE APE_AREA_OBJID = " & lblAreaOBJID.Text & " AND EMPLOYEE_NAME = '" & EMPLOYEE & "' AND YEAR_TIME = '" & cbYear.Text & "' AND ACTIVE = 1) AS RESULT1" & _
" FROM dbo.APE_BUSDRIVER_MAIN "
Using connection As New SqlConnection(SQLConnectionStr)
Dim command As New SqlCommand(queryString, connection)
connection.Open()
Dim reader As SqlDataReader = command.ExecuteReader()
If reader.Read Then
RESULT1 = reader("RESULT1")
Else
RESULT1 = 0
End If
End Using
End Sub
You have opened the reader, but have not asked it to actually read anything.
After this line:
Dim reader As SqlDataReader = command.ExecuteReader()
add
If reader.Read() Then
and wrap the result reading into this if statement, i.e.
If reader.Read() Then
Dim index As Integer = reader.GetOrdinal("RESULT1")
If reader.IsDBNull(index) Then
RESULT1 = String.Empty
Else
RESULT1 = reader(index)
End If
End If
Note that this works because your SQL should only return a single record. In the event that you were reading multiple records, you would need to call the Read statement in a loop until there were no more records, i.e.
Do While reader.Read()
Loop
I wanted to provide another, more-advanced, answer as an option. Many classes can be extended in .NET like this.
If you are regularly performing "Is NULL" checks like this in your applications, you can choose to extend the DataReader class once to have additional functions available everywhere in your application. Here is an example that creates an extension called "ReadNullAsString()" onto the data reader class. This makes a function that always returns String.Empty when a DbNull is encountered.
Part 1, place this module code in a new class file in App_Code if application is a website, otherwise place where ever you prefer. There are two overloads, one for the field's ordinal position (aka index), and one for the field's ColumnName.
Public Module DataReaderExtensions
''' <summary>
''' Reads fieldName from Data Reader. If fieldName is DbNull, returns String.Empty.
''' </summary>
''' <returns>Safely returns a string. No need to check for DbNull.</returns>
<System.Runtime.CompilerServices.Extension()> _
Public Function ReadNullAsEmptyString(ByVal reader As IDataReader, ByVal fieldName As String) As String
If IsDBNull(reader(fieldName)) Then
Return String.Empty
Else
Return reader(fieldName)
End If
Return False
End Function
''' <summary>
''' Reads fieldOrdinal from Data Reader. If fieldOrdinal is DbNull, returns String.Empty.
''' </summary>
''' <returns>Safely returns a string. No need to check for DbNull.</returns>
<System.Runtime.CompilerServices.Extension()> _
Public Function ReadString(ByVal reader As IDataReader, ByVal fieldOrdinal As Integer) As String
If IsDBNull(reader(fieldOrdinal)) Then
Return ""
Else
Return reader(fieldOrdinal)
End If
Return False
End Function
End Module
Step 2, call the new extension like so:
' no need to check for DbNull now, this functionality is encapsulated in the extension module.
RESULT1 = reader.ReadNullAsEmptyString(index)
'or
RESULT1 = reader.ReadNullAsEmptyString("RESULT1")
I know I'm being an idiot here and I just can't work it out. But i'm trying to take some data back from a vb.net database. It's falling over with a Object reference not set to an instance of an object error. And before the code runs it's saying the variable is being used before it's set, but I can't see how. Code:
Private taNotifications As dsDataTableAdapters.NotificationsTableAdapter = New dsDataTableAdapters.NotificationsTableAdapter
Dim notification As dsData.NotificationsDataTable = taNotifications.GetDataByClientID(userrow.UserID)
If notification.Rows.Count > 0 Then
Dim notificationrow As dsData.NotificationsRow
Dim forwardURL As String = notificationrow.ForwardLocation
End If
It falls over on the Dim forwardURL As String = notificationrow.ForwardLocation
The problem is that you have never instantiated the notificationRow inside the if statement. You've declared it, but it doesn't belong to anything. You need to make an assignment or loop through your rows before doing anything with this object:
Dim notificationrow As dsData.NotificationsRow ' this is not instantiated
Dim forwardURL As String = notificationrow.ForwardLocation
What you really want in this case is:
For Each notificationRow As dsData.NotificationRow In notification
Dim forwardURL As String = notificationRow.ForwardLocation
' Do Something
Next
If you only HAVE one row and you know you only have 1 or 0 rows then you could use your if statement by doing:
If notification.Rows.Count > 0 Then
Dim notificationrow As dsData.NotificationsRow = _
CType(notification.Rows(0), dsData.NotificationsRow)
Dim forwardURL As String = notificationrow.ForwardLocation
End If
Edit: In the code above, I originally just had notification.Rows(0). This will produce a DataRow object, but it will not be strongly typed. You need to perform the CType that I added in order to use the custom property ForwardLocation.
You never set notificationrow to anything. Did you mean to set it like this?
Dim notificationrow As dsData.NotificationsRow = CType(notification.Rows(0), dsData.NotificationsRow)
I wrote the following function that works about 95% of the time, but I need it to work 100% (obviously):
Public Shared Function getPassedVars() As String
Const keyCount As Integer = 54 ' 54 seems to be the number of parameter keys passed by default (for this web_app).
' there are more if there is a form involved (ie. from search page)
Dim oParams As String = ""
Try
With HttpContext.Current
If .Request.Params.AllKeys.Count > keyCount Then
For i As Integer = 0 To (.Request.Params.AllKeys.Count - (keyCount + 1))
oParams &= String.Format("{0}={1}{2}", .Request.Params.Keys.Item(i), .Request.Params(i), IIf(i < .Request.Params.AllKeys.Count - (keyCount + 1), ";", ""))
Next
End If
End With
Return oParams
Catch ex As Exception
Return Nothing
End Try
End Function
It scrubs the Request.Params object for passed variables, which are in the beginning of the array (the remaining ones are ASP parameters). I am pretty sure I've seen a different way to get these parameters, but I haven't been able to figure it out. Any suggestions?
EDIT
So it looks like I can use the Request.URL.Query to achieve this, I will investigate this and post back.
Here is what I came up with:
Public Shared Function getPassedVars() As String
Dim oParams As String = ""
Dim qString As String = ""
Dim oSplit As New List(Of String)
Try
With HttpContext.Current
qString = .Request.Url.Query
If qString.Length > 0 Then 'do we have any passed variables?
If qString.StartsWith("?") Then qString = qString.Remove(0, 1) 'remove leading ? from querystring if it is there
oSplit.AddRange(qString.Split("&"))
For i As Integer = 0 To oSplit.Count - 1
oParams &= String.Format("{0}{1}", oSplit.Item(i), IIf(i < oSplit.Count - 1, ";", ""))
Next
Return oParams
Else
Return Nothing
End If
End With
Catch ex As Exception
Return Nothing
End Try
End Function
So far so good.
Request.QueryString is a NameValueCollection, so the easiest way to get the "parameters" is to do the following:
foreach (String s in Request.QueryString) {
Response.Write(s + " = " + Request.QueryString[s]);
}
Where is your function located? If it's executing in the page's code behind then you definitely do not need to use the HttpContext variable.
It looks like you are trying to get values from the query string.
For example, for this URL:-
http://www.tempuri.org/mypage.aspx?param1=x¶m2=y
I assume you want retreive the values of the query string parameters param1 and param2?
If so, just use:-
Dim param1 as String = Request.QueryString("param1")
Otherwise, if these parameters are contained in a form (an HTTP POST request) then use the method which Mitchel Sellers suggests.
If you know the name you can use the following to get it by key value
Dim myParamValue as String = Request.Form("MyKeyName")
Otherwise, you can loop through the form collection, by key etc, to get the values. The key is, do you really need to be parsing all 54 items? Or are you simply looking for a few specific values?
httpcontext.Current.Request.QueryString("KeyName")
Request.Params will contain the query parameters you're after.
There's no need to parse the info from Request.URL since it's already done for you.