NullReferenceException only Live not in development environment

Hi all,

i have an strange error and i don`t find an solution for this.

My Code is running great in development. But when i publish it i get an NullReferenceException.

I hope someone can help.

This is the Code:

private void lblDragSource_MouseDown(object sender, MouseEventArgs e)
{
Label clickedLabel = sender as Label;

movingRoom = (SplitterPanel)clickedLabel.Parent;
startingRoom = movingRoom.Parent as SplitContainer;

if (e.Button == MouseButtons.Left)
{
clickedLabel.DoDragDrop(clickedLabel.Text,
DragDropEffects.Move);
}
if (e.Button == MouseButtons.Right)
{
SplitterPanel splitterPanel = clickedLabel.Parent as SplitterPanel;
GroupBox currentRoom = splitterPanel.Parent.Parent as GroupBox;
DatabaseRoom currentDbRoom = rooms.Where(r => r.name == currentRoom.Text).FirstOrDefault();
Employee employeeToRemove = currentDbRoom.employees.Where(em => em.angName == clickedLabel.Text).FirstOrDefault();
if (employeeToRemove != null)
{
currentDbRoom.employees.Remove(employeeToRemove);
employeeToRemove.removeFromRoom();
}
updateRooms();
}
}

Attachment

WisejError.JPG

General

Tom Oeben asked Mar 5, 2021 - 9:38 am

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Answers (5)

Will do but why the hell i don`t get the same error in Visual Studio ?

When i start the app there everything is working great. Same Browser etc………

If one of them would return null wouldn`t i get the same error in VS ?

Tom Oeben answered Mar 5, 2021 - 2:19 pm

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Will do but why the hell i don`t get the same error in Visual Studio ?

When i start the app there everything is working great. Same Browser etc………

If one of them would return null wouldn`t i get the same error in VS ?

Tom Oeben answered Mar 5, 2021 - 2:18 pm

- Luca
- Mar 5, 2021 - 3:03 pm
The browser is not related. I don’t know your deployment, could be different files, etc. You can attach VS to the web server and see.
- Tom Oeben
- Mar 5, 2021 - 4:19 pm
Ok the error is here: movingRoom = (SplitterPanel)clickedLabel.Parent; The Label has NO Parent. In Visual Studio it has. Live it has not…..getting mad over it :)
- Tom Oeben
- Mar 5, 2021 - 4:21 pm
Btw same files. I publish from Visual Studio over webDeploy to the server

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So now you know that the NullReference is in lblDragSource_MouseDown, which you already knew. Looking at your code, these are the only possible places, since NullReferenceException is not caused by Wisej:

Label clickedLabel = sender as Label;
movingRoom = (SplitterPanel)clickedLabel.Parent; <-- clickedLabel can be null if the cast above is wrong. Change to a cast or check what the sender is.

If clickedLabel is not null, then:

SplitterPanel splitterPanel = clickedLabel.Parent as SplitterPanel;
GroupBox currentRoom = splitterPanel.Parent.Parent as GroupBox; <-- if the parent of clickedLabel is not a SplitterPanel you get null. Change to a cast or check.

DatabaseRoom currentDbRoom = rooms.Where(r => r.name == currentRoom.Text).FirstOrDefault(); <-- Same as above.

Basically looks like one of the “as” conditional casts fails returning null. Change it to a cast and it will generate an InvalidCastException.