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Dear Freind,
So many times i posted my questions in this forum , but never i got a satiesfied answer, don't know why?
again following i m posting the query which is raised at the time of executing the program.
Private Sub txtplno_LostFocus(ByVal sender As Object, ByVal e As System.EventArgs) Handles txtplno.LostFocus
Dim str As String
Dim com As SqlCommand
Dim conn As New SqlConnection("Data Source=toshiba-pc;Initial Catalog=VRINDAVAN;User ID=sa;password=zion123")
conn.Open()
str = ("select count(*)from plotmaster where plotno='" + txtplno.Text & "'")
com = New SqlCommand(str, conn)
Dim count As Integer = Convert.ToInt32(com.ExecuteScalar())'**----the error comes here**
conn.Close()
If count > 0 Then
MessageBox.Show("Plot No. already Exist")
txtplno.Text = ""
txtplno.Focus()
Else
txtpsize.Focus()
dgvstatus2.EditMode = DataGridViewEditMode.EditOnKeystrokeOrF2
conn.Close()
End If
End Sub
this code is working properly that it's checks the existing record and if exist it throw message that data already exist,and not the cursor goes to next text field after filling the all text boxes just i click on add button it's shows that successfully saved, but when i click on gridview it's display the message at where i indicating above followed by asterisk,and the error is in subject line.
please do needful
below is my table structure
CREATE TABLE [dbo].[plotmaster](
[pkid] [int] IDENTITY(1,1) NOT NULL,
[plotno] [numeric](5, 0) NULL,
[plotsize] [varchar](10) NULL,
[block] [varchar](5) NULL,
[sqyards] [numeric](10, 0) NULL,
[rate] [numeric](18, 0) NULL,
[plot_total_rate] [numeric](18, 0) NULL,
[Book_amt] [numeric](18, 0) NULL,
[date] [smalldatetime] NULL,
[referance] [varchar](50) NULL,
[status] [varchar](15) NULL,
CONSTRAINT [PK_plotmaster_1] PRIMARY KEY CLUSTERED
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Member 10192835 wrote: So many times i posted my questions in this forum , but never i got a satiesfied answer, don't know why?
This appears to be your third forum post. The other two posts have several answers, and you haven't responded to any of them. If you don't reply to an answer, then how is anyone supposed to know whether the answer has worked?
Your posts generally show very little effort, as they include large code dumps with no formatting. They also include phrases such as "do needful" and "send me the solution urgently". Nobody here is paid to answer your questions, and demanding immediate answers from volunteers is a good way to make sure your question is ignored.
Member 10192835 wrote: Dim conn As New SqlConnection("Data Source=toshiba-pc;Initial Catalog=VRINDAVAN;User ID=sa;password=...
Not a good idea to post your sa password in a public forum! I suggest you change it immediately.
It's also not a good idea for your application to connect to the database as a system administrator. Either use integrated authentication, or create a specific user with the minimum permissions necessary for your application to run.
Hard-coding the connection string throughout your code is also a bad idea. You should store the connection string in the configuration file:
How to get Connection String from App.Config in C#[^]
Member 10192835 wrote: str = ("select count(*)from plotmaster where plotno='" + txtplno.Text & "'")
Your application is wide open to SQL Injection[^]. If the user types ';delete plotmaster-- and tabs away from the textbox, your entire table will be deleted.
Even worse, since you're connecting as sa, the user can gain complete control of your database server.
ADO.NET makes it extremely easy to use a parameterised query[^], so there's no excuse for not doing so.
The plotno column is defined as numeric(5, 0) (essentially a restricted int), but you're trying to compare it to a string. SQL will try to convert the string to a number; if it fails, you'll get the error you're seeing. You need to validate that the text is actually a number before you try to execute your query.
Private Sub txtplno_LostFocus(ByVal sender As Object, ByVal e As System.EventArgs) Handles txtplno.LostFocus
Dim plotno As Integer
If Not Integer.TryParse(txtplno.Text, plotno) Then
Return
End If
Using conn As New SqlConnection("...")
Using com As New SqlCommand("SELECT COUNT(*) FROM plotmaster WHERE plotno = @plotno", conn)
com.Parameters.AddWithValue("@plotno", plotno)
conn.Open();
Dim count As Integer = Convert.ToInt32(com.ExecuteScalar())
If count > 0 Then
MessageBox.Show("Plot No. already Exist")
txtplno.Text = ""
txtplno.Focus()
Else
txtpsize.Focus()
dgvstatus2.EditMode = DataGridViewEditMode.EditOnKeystrokeOrF2
End If
End Using
End Using
End Sub
"These people looked deep within my soul and assigned me a number based on the order in which I joined."
- Homer
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Hello
I will take care further and i just want to do best,
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Member 10192835 wrote: So many times i posted my questions in this forum , but never i got a satiesfied answer, don't know why?
Firstly, you have not indented your code, or put the correct formatting around it. You should use <pre> tags, automatically generated by the code button, above the edit box, so it looks like:
Private Sub txtplno_LostFocus(ByVal sender As Object, ByVal e As System.EventArgs) Handles txtplno.LostFocus
Dim str As String
Dim com As SqlCommand
Dim conn As New SqlConnection("Data Source=toshiba-pc;Initial Catalog=VRINDAVAN;User ID=sa;password=zion123")
conn.Open()
str = ("select count(*)from plotmaster where plotno='" + txtplno.Text & "'")
com = New SqlCommand(str, conn)
Dim count As Integer = Convert.ToInt32(com.ExecuteScalar())
conn.Close()
If count > 0 Then
MessageBox.Show("Plot No. already Exist")
txtplno.Text = ""
txtplno.Focus()
Else
txtpsize.Focus()
dgvstatus2.EditMode = DataGridViewEditMode.EditOnKeystrokeOrF2
conn.Close()
End If
End Sub
Secondly, a quick look at the documentation[^], would probably give a clue as to what you are doing wrong.
Veni, vidi, abiit domum
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is it possible to have a duplicate uuid generated in vb.net?
MsgBox(Guid.NewGuid().ToString)
What???
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In theory, yes. In practice, no.
Why?
Bastard Programmer from Hell 
If you can't read my code, try converting it here[^]
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A Guid is 128 bit. Therefore you would have to generate 2^128 + 1 GUIDs to encounter a single GUID twice.
A thread on StackOverflow.com[^] says that you would need about 10790283070806014188970 years to encounter a single GUID twice, assuming your program does nothing else than creating GUIDs and runs at a processor speed of 1 GhZ, without any interruption by CPU power eaten by other programs or the operating system itself.
As you probably can think now, encountering the same GUID twice would be very bad luck and can safely considered as being unrealistic.
People becoming wiser in order to notice the stupid things they did back in the young days. This doesn't mean that they really stop doing those things. Wise people still do stupid things, only on purpose.
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Marco Bertschi wrote: Therefore you would have to generate 2^128 + 1 GUIDs to encounter a single GUID twice.
Not quite. GUIDs aren't entirely random, so you'd only need 2122 to get a collision with a specific GUID. To get a collision anywhere within the set of generated GUIDs, you'd only need to generate around 261 GUIDs.
Eric Lippert goes into more detail in part 3 of his GUID guide series[^].
"These people looked deep within my soul and assigned me a number based on the order in which I joined."
- Homer
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Richard Deeming wrote: Not quite. GUIDs aren't entirely random, so you'd only need 2122 to get a collision with a specific GUID. To get a collision anywhere within the set of generated GUIDs, you'd only need to generate around 261 GUIDs.
Yep - Mark has posted about my brain glitch[^], too.
People becoming wiser in order to notice the stupid things they did back in the young days. This doesn't mean that they really stop doing those things. Wise people still do stupid things, only on purpose.
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What was working well on Windows NT 4 does not work on Windows XP. What am I doing wrong? It starts Paint in a new window with the correct file, but the keys do not get sent to it.
Dim PaintCommand As String, PaintPath As String
Call PaintDir(PaintPath)
PaintCommand = PaintPath & "MSPAINT.EXE " & Filename1
If InStr(PaintPath, "WINNT") Then
Xnothing = Shell(PaintCommand, 1)
SendKeys "%FA{TAB}{DOWN}{DOWN}{DOWN}{DOWN}{DOWN}{UP}{UP}{UP}{TAB}{ENTER}Y%FX", True
End If
If InStr(PaintPath, "WINDOWS") Then
If IsVista() = 1 Then
Exit Sub
Else
Xnothing = Shell(PaintCommand, 1)
SendKeys "%FA{TAB}{DOWN}{DOWN}{DOWN}{DOWN}{DOWN}{UP}{UP}{UP}{UP}{UP}{UP}{TAB}{ENTER}YY%FX", True
End If
End If
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You're launching Paint, but not waiting for it to start before sending keys to it.
This is one of the long list of problems with using SendKeys...
If you're using VB.NET, you should being the Process class to start another process, not Shell.
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Thanks for your response. How best do I wait until Paint has started?
Should I need AppActivate PAINT or MSPAINT? It does not work, and I can't find the name of the program.
Even causing a delay by unnecessary calculations did not solve the problem. The focus does not shift to the Paint window. It send the keys to the window in the VB6 program.
modified 23-Oct-13 7:24am.
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It's already going to be activated.
You have to use the Process class to start Paint, then you call the WaitForInputIdle method on it which will block your code until Paint starts and is ready for input. Then you can use SendKeys.
The problem with SendKeys is what if the user clicks on some other app? All the keys you're sending will then go to that application, not Paint...
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Dave Kreskowiak wrote: It's already going to be activated.
Not in VB6; there's a feature that prevents other apps from stealing the focus.
Bastard Programmer from Hell
If you can't read my code, try converting it here[^]
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The code he posted hints that he's using VB6, but we don't know for sure. He hasn't said what he's actually using.
But, you are correct.
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Dave Kreskowiak wrote: It's already going to be activated.
You have to
use the Process class to start Paint, then you call the WaitForInputIdle method on it which will block your code until
Paint starts and is ready for input. Then you can use SendKeys.
The problem with SendKeys is what if the user
clicks on some other app? All the keys you're sending will then go to that
application, not Paint...
Yes, I am using VB6 on Windows XP.
The focus does not go to Paint. AppActivate also does not do anything either with the name or with the process number.
The user is nobody other than me, so there is little risk of the user clicking another window while Paint is doing its job in 1 second or so.
How do I use WaitForInputIdle? Is that some API command?
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THe entire problem is that you Shell Paint and then you immediately try to Activate it or SendKey to it. Well, Paint hasn't started yet, so those operations do nothing because Paint doesn't have a window yet.
You have to wait for Paint to start and show itself before you can do anything else with it.
In VB.NET, this is two lines of code, uising the Process class. In VB6, it's a bunch more. You don't have a Process class and, hence, you don't have WaitForInputIdle either. You have to write this code yourself.
In VB6, you'd launch Paint, then call the Win32 API function OpenProcess to get the process handle, pass that handle to the Win32 function WaitForInputIdle, then call ReleaseProcessHandle on the handle you got. Seems simple enough, right? Try getting the handle to a Process that hasn't completely started yet...
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I am a little novice in VB programming. I am trying to write a program related to Retail sales where I need to move the MRP to other fields whenever the MRP changes. I have three fields which I intend to update as and when MRP Changes. So the first time the MRP Changes the old MRP will move to MRP1 field. Subsequently to MRP2 and MRP3 field. Next time it should again update MRP1. Can anybody help me on how to do this using SQL updates. I am using VS2008 with MySQL.
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You're going to have to confirm what your database schema is laid out like.
From the sounds of it, you're doing it VERY wrong. You should not have columns in the same table, labeled MRP, MRP1, MRP2, ... and moving the data from column to column. This results in having only a limited, fixed number of updates possible.
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Hi Dave
Thanks for the reply. The Database schema is as follows:
Prodcode Varchar(15)
MRP Double(15,2)
MRP1 Double(15,2)
MRP2 Double(15,2)
MRP3 Double(15,2)
I actually did not understand why you say that the updates will limited. I can understand that the information with respect to MRP changes will be limited to 3 + current. This is ok with me. I don't want to create another table to keep this information as the requirement of keeping the details of MRP change will be enough with a level of 3. Also since I am dealing with FMCG products, and since the rate changes are quite frequent, with huge number of SKUs, I don't want to create another table and utilize additional disk space.
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It's not the correct way of doing this, but, it's your system...
What you lose doing it your way is the ability to roll back any mistakes. History values will be lost if your updates exceed 3 and you try to roll it back. Also, if the user makes a mistake and hits your UPDATE button twice (if not handled properly!), say, in a web app, you could commit the same change to the record more than once and not be able to roll it back.
It's possible to do in a single SQL UPDATE statement. From my feeble memory...
UPDATE yourTable
SET
MRP = @parameterNewValue,
MRP1 = MRP,
MRP2 = MRP1,
MRP3 = MRP2
WHERE Id = @parameterRecordId
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Hi Dave
Thank you so much for the reply. I agree that this is not the correct way of doing it but this is what is the requirement. I know that by keeping a separate table I will not only have the benefit of rollback to any times backward but also I can produce many important reports like price change frequencies, % price changes etc.
Thanks again
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Yeah, you can also do "many important reports" by doing it the correct way. Sure, the SQL is a little more complicated, but it's a LOT safer for your data.
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What you should be doing (as Dave implied) is redesign your table structure so there is 1 MRP field on your product table and a related table containing the history of the MRPs
lnkProductMRP
ProductID int
MRP Double(15,2) (why is this 2 decimal places and not an int)
Modified DateTime - when it was changed
ModifiedBy varchar(##) - who did the deed
Reason varchar(###) - Why the change of MRP
This retains your history past 3 events, allows roll back, and records the person and reason for the change.
Never underestimate the power of human stupidity
RAH
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