When triggered for the first time, the value is 0.

When picking BMP = not picking BMP is executed, the value is-1.

Because it is a static variable, the value is still-1 when it is triggered for the second time.

When executed to pickbmp = Not pickbmp, the value is 0.

Continue to trigger .......

You can think of it as a Boolean variable. In fact, the true and false values of Boolean variables in vb are-1 and 0.