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Private Sub DGV_studs_SelectionChanged(ByVal sender As Object, ByVal e As System.EventArgs) Handles DGV_studs.SelectionChanged
       Dim i As Integer = DGV_studs.CurrentRow.Index

       Me.lbl_studID.Text = DGV_studs.Item(1, i).Value.ToString()
       Me.txt_fullname.Text = DGV_studs.Item(2, i).Value.ToString()
       Me.txt_email.Text = DGV_studs.Item(3, i).Value.ToString()
       Me.txt_contact.Text = DGV_studs.Item(4, i).Value.ToString()
       Me.txt_address.Text = DGV_studs.Item(5, i).Value.ToString()
       Me.txt_age.Text = DGV_studs.Item(6, i).Value.ToString()
       Me.txt_bdate.Text = DGV_studs.Item(7, i).Value.ToString()
       Me.cmb_position.Text = DGV_studs.Item(8, i).Value.ToString()
       Me.lbl_imagename.Text = DGV_studs.Item(9, i).Value.ToString()

   End Sub


What I have tried:

Hi there whenever Im clicking the column names in datagridview im getting this error "Object reference not set to an instance of an object."
Posted
Updated 31-Oct-19 0:42am
Comments
Richard MacCutchan 31-Oct-19 5:26am
   
Where is the code that handle the column name click?
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Solution 1

This is one of the most common problems we get asked, and it's also the one we are least equipped to answer, but you are most equipped to answer yourself.

Let me just explain what the error means: You have tried to use a variable, property, or a method return value but it contains null - which means that there is no instance of a class in the variable.
It's a bit like a pocket: you have a pocket in your shirt, which you use to hold a pen. If you reach into the pocket and find there isn't a pen there, you can't sign your name on a piece of paper - and you will get very funny looks if you try! The empty pocket is giving you a null value (no pen here!) so you can't do anything that you would normally do once you retrieved your pen. Why is it empty? That's the question - it may be that you forgot to pick up your pen when you left the house this morning, or possibly you left the pen in the pocket of yesterdays shirt when you took it off last night.

We can't tell, because we weren't there, and even more importantly, we can't even see your shirt, much less what is in the pocket!

Back to computers, and you have done the same thing, somehow - and we can't see your code, much less run it and find out what contains null when it shouldn't.
But you can - and Visual Studio will help you here. Run your program in the debugger and when it fails, VS will show you the line it found the problem on. You can then start looking at the various parts of it to see what value is null and start looking back through your code to find out why. So put a breakpoint at the beginning of the method containing the error line, and run your program from the start again. This time, VS will stop before the error, and let you examine what is going on by stepping through the code looking at your values.

But we can't do that - we don't have your code, we don't know how to use it if we did have it, we don't have your data. So try it - and see how much information you can find out!
   
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Solution 2

Me.lbl_studID.Text = DGV_studs.Item(1, i).Value.ToString()


You'll get that error if any of the following are Nothing;

Me
Me.lbl_studID
DGV_studs
DGV_studs.Item(1, i)
DGV_studs.Item(1, i).Value

For the line that is giving the error (it's slightly concerning that you don't think the line that throws the error is relevant information that you would include in the question) check each part to see what is Nothing and go from there. Either it is Nothing when it shouldn't be due to an error elsewhere, or Nothing is a valid scenario and you have to code to deal with it. We don't have access to your data so we can't do any of that for you, and we don't know what your required logic is so can't tell you what the fix is.
   

This content, along with any associated source code and files, is licensed under The Code Project Open License (CPOL)

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