There is a class in this datalayer that subclasses System.Data.Datatable. So for example if I populated a System.Data.Dataset and then tried to put the first table of this dataset into this class like so:
Code:
Dim dt as new myDatable
dt = ds.Tables(0)
[code]....
Is there a way in vb.net to subclass/hooking in to any controls scroll bar and change it is colours etc (I saw this once in C++ but lost it). It�s ok for MS giving us user owner drawn controls, or at the very least allowing us to draw the controls information but it looks dam write awful if the scroll bar does not fit into the GUI.
View 8 RepliesI used this code:
Code:
Friend Sub PopulateCB(ByRef mycontrol As ComboBox, _
ByVal expressionSQL As String)
' DMBD is my data-handling class:
[code]...
Nevertheless, mycontrol remains empty after this.
I have a datagridview which is populated from a datatable. This works fine. But if i run it more then once i get a column name "example" already belongs to this datatable. Ive tried everything to clear all the columns of the datatable and the gridview but still the same
[Code]...
I have one specific problem, that is relative to DataTable Updates to Database.
Code:
auxDatatable = Mydataset.MyDatatable.GetChanges
Now i'm going to Accept or Reject Changes based on some Criteria. The problem is that I wish to Update Only the Records that in Fact exist on the Database, as you can imagine I was forced to create some Dummy Records in Datatable, to a specific job.
My approach to this issue was to do something like this :
Code:
Private Sub MySub (ByVal auxDatatable As DataTable)
Dim drView As Mydataset.Mydatatable
For i As Integer = 0 To auxDatatable.Rows.Count - 1
[CODE]...
As you can see I tried to Delete the rows that are Dummys, but the rows in fact are not being deleted. As consequence I get an error after that Sub, when i try to make :
Code:
MyTableAdapter.Update(auxDatatable)
This is naturaly caused by the dummy Records.
I have an application where I would like to allow the user to change one field in a datatable but leave the other ones uneditable. I am using a datagridview to do this but I can only make the whole table editable or not. The result should be an order form where you have a determined product and should only be able to change the number of items.
View 2 RepliesI am trying to summarize a datatable based on a primary column and then add certain columns. For example this table
col-1 col-2 col-3
1 AA 2
2 BB
[Code].....
This simply doesn't do anything becuase it thinks the target table doesn't have a primary key.
I am trying to search a datatable using a compound key. I can create the compound key just fine, but when I go to create an object to pass to the find it give me an error. Below is a sample of my code.
dim lblDT...etc...
Here is where I create the compound key, and it seems fine.
lblDT.PrimaryKey = New DataColumn() {
lblDT.Columns("serialno"), _
lblDT.Columns("type")}
This is where I am trying to create an object to pass to the .find
dim objSearch As New Object() {10643, 28}
It if would work this is how the find would be.
Dim row As DataRow = lblDT.Rows.Find(objSearch)
I have been having trouble finding a good way to do this. Basically what I need to do is take a query from a SQL Server Database and place it into a DataTable (or an array) for manipulation. I've got the connection and everything working, but none of the methods I've tried so far seem to work very well.I need it to compare data with an uploaded CSV file and post on a website.
View 1 RepliesI have two applications Application 1:source
Public
Class Form1
Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
Button1.Enabled =
[Code]...
I want to create a subclass of a class that has some shared methods. These shared methods all call one specific method. But I can't redefine that specific method in the subclass. If I try to make it overridable in the parent class, it says that shared and overridable can't both be used.
[Code]...
i used an old VB6 algorithm to subclass a window and made a few changes at the 'hook method' to make it work in .NET.
Private Declare Function SetWindowLong Lib "user32.dll" Alias "SetWindowLongA" (ByVal hWnd As Integer, ByVal nIndex As Integer, ByVal dwNewLong As delWindowProc) As Integer
[Code].....
Probably a very dumb question but I have a program whereby I create and populate an in memory datatable, which I then add to a data-set. I then run a couple of updates on the dataset and need to know how to then send these updates down into the in memory datatable :Here is a mock up of the code structure following the creation and population of the table :
[Code]...
I need help with this line of code: Me.avgsalespricetxt.Text = Me.dtsold.Compute("AVG(Convert([Selling Price]),'System.Int32'))")
Here is all the code i have so far, I need to Average a column in my datatable from what i have read "Compute method supports expressions and they support CONVERT function that you could use inside of the expression."
[Code]...
I'm listening for the WM_SETCURSOR messages and setting the cursor there, it works most times, but not always. I've seen two other cases that I need to catch:
WM_PAINT: At least after a WM_LBUTTONDOWN the cursor is painted somehow without calling WM_SETCURSOR... WM_CAPTURECHANGED: Happening sometimes when the mouse is down and moving it.
Even doing all this the cursor sometimes flickers and the original one can be seen in some cases (eg: the instant when you roll over some object that sets the cursor to something else). I've been trying to look for some other patterns or messages but didn't see anything that would solve this problem.
I'm retooling an app, and condensing my queries down to one, but to do so, I would like to move the columns for better presentation. I am reporting on errors for particlular equipment, and the user may want to get equipment by errors or errors by equipment. Is there any way to change column order?
View 5 RepliesSource: DataTable
Destination: Access Database Table
I should mention that the DataTable contains data resulted by an SQL SELECT query and it's not related to the "targeted" Access Database Table.
Dim CustID As String = txtSrchCustID.Text
Dim FirstName As String = txtNewCustFName.Text
Dim SecondName As String = txtNewCustSName.Text
If CustID And FirstName And SecondName = "" Then
MsgBox("Please enter a term to search by")
EndIf
This returns "Conversion from string "" to type 'Long' is not valid." I was wondering what the error is and how it's possible to fix it? The other questions that I've looked at were mostly to do with variables assigned incorrect types, but I think that isn't the issue. It occurs when all of the variables are empty.
OK, this is going better, now im stuck in the mud again, i am trying to get a form to print,this works now, however i would like to enable a few frames with text boxes for a few seconds to allow the printer to print the text in black instead of gray. he error i am getting is this, as the timer disables:" Unable to cast object of type System.Windows.Forms.Timer' to type 'System.Windows.Forms.ToolStripMenuItem'. "
Public
Sub
Print_Renamed_Click(ByVal
[code].....
I have a field named 'UserID' in my OLE database with the type 'Autonumber'. But when I try to cast it to a variable of type 'String' I get an an InvalidCastException - Specified cast is not value.
View 16 RepliesPrivate Sub gvDesignGVnote_CellClick(ByVal sender As System.Object, ByVal e As System.Windows.Forms.DataGridViewCellEventArgs) Handles gvDesignGVnote.CellClick
If e.RowIndex < 0 Then[code]......
I'm using a C# API wrapper library for connection to a program. It has worked very well for a long time, but now I have this error I can not get out of. The error occurs inside the library code (which I have not modified). It gives the following pop-up window:I believe I had this or similar type of error some times before (at least the first pop up was similar), and then I believe I just clicked "Build solution", or rebuild, and it would work. But this time not...
View 2 RepliesI am making a simple calculator and it's saying InvalidCastException was unhandled when I try to debug it, here's the code, please tell me whats wrong with it: (and yes I have renamed the textboxes to addequals etc...
Public Class Form1
Private Sub WebBrowser1_DocumentCompleted(ByVal sender As System.Object, ByVal e As System.Windows.Forms.WebBrowserDocumentCompletedEventArgs)
End Sub
[code].....
I am using Visual Studio 2005, Version 2.0. Coding a windows application with VB.NET.I am trying to use a textbox (txtLogCall) to display matched results in a datagrid. I have added a bindingsource and have the dataset and tableadapter.
I have set the databinding tag of the datagrid to the field that I want to use as a parameter. The textbox is for an Caller's Name, so I have set the datagrid tag to 'EmergencyCallerIdentification' that is in the table.
[Code]...
I have some trouble in SMS gateway project using VB.Net (VS 2010)while programme was running, I found error "InvalidCastException was Unhandled", then my programme cannot continue. below I copy the code of the programme :
----------------------------------------------------------------------------------------------------------------------
Option Explicit On
Public Class MessageReceiver
Private TPMessageTime As String
[code]....
I have a Linq Group By query that works. Here's the query:
Dim query = From fb As Feedback In lst Where fb.Seller.login_name.ToLower = UserName.ToLower
Order By fb.transaction_id Descending, fb.creation Descending _
[Code]...
I don't like working with anonymous types so I'm trying to delare the result and am hitting an InvalidCastException.
Here's the type information:
Debug.Print(query.GetType.ToString)
Returns:
System.Linq.GroupedEnumerable`4[Feedback,System.Nullable`1[System.Int32],Feedback,VB$AnonymousType_0`2[System.Nullable`1[System.Int32],System.Collections.Generic.IEnumerable`1[Feedback]]]
[Code].....
I have a Linq Group By query that works. Here's the query:
Dim query = From fb As Feedback In lst Where fb.Seller.login_name.ToLower = UserName.ToLower
Order By fb.transaction_id Descending, fb.creation Descending _
Group fb By fb.transaction_id _
Into Group
I don't like working with anonymous types so I'm trying to delare the result and am hitting an InvalidCastException.
Here's the type information:
Debug.Print(query.GetType.ToString)
Returns:
System.Linq.GroupedEnumerable`4[Feedback,System.Nullable`1[System.Int32],Feedback,VB$AnonymousType_0`2[System.Nullable`1[System.Int32],System.Collections.Generic.IEnumerable`1[Feedback]]]
and the inner type:
Debug.Print(item.GetType.ToString)
Returns:
VB$AnonymousType_0`2[System.Nullable`1[System.Int32],System.Collections.Generic.IEnumerable`1[Feedback]]
So, armed with this information, here's the declaration used:
Dim query As IEnumerable(Of IGrouping(Of Int32?, IEnumerable(Of Feedback)))
Here's the error returned:
Unable to cast object of type 'System.Linq.GroupedEnumerable`4[Feedback,System.Nullable`1[System.Int32],Feedback,VB$AnonymousType_0`2[System.Nullable`1[System.Int32],System.Collections.Generic.IEnumerable`1[Feedback]]]' to type
[code]....
I am trying to catch the System.InvalidCastException error. If I put a number into the calculator the program runs ok. If the calculate button is pressed with nothing in the text boxes I get the casting error Conversion from string "" to type 'Decimal' is not valid. I understand why I am getting the error. I don't know what to do about it. I want the program to dump null data and go back to waiting for input from the user.
Private Sub btnCalculate_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnCalculate.Click
Dim FedTaxRate = 0.13 ' constants for taxes and work week
[code].....
I'm programming a slideshow in Visual basic and get a SystemInvalidCastException when trying to initialize an array through a For Each loop. Here's what I'm trying to do. I have an array of Images() and another array of ImageNames(). Now I store all my images on a website, let's sa so for ease of use, I've named all my images in this manner
View 3 RepliesI've got a typed dataset. I bind the data with a binding source to a form with arround 200 textboxes, dataedits and so on. Everything works fine with one exception:In my database I have empty DateTimes (DBNull.Value). And when they get bound to a DateEdit-Control, I get the following exceptions:
A first chance exception of type 'System.InvalidCastException' occurred in Microsoft.VisualBasic.dll
A first chance exception of type 'System.Data.StrongTypingException' occurred in myTestDLL.dll
I tried to change the NullValue-Property in the DataSet-Desinger to something else as 'Throw Exception', but it doesn't work for a DateTime. For other types like Integer or String it works fine.I dont know a nice solution (right now I fill the empty dates with some dummy date and make it invisible in the DateEdit-Control, but this is very uncool) and I hope to find some help here.
