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Unable to cast object of type 'System.DBNull' to type 'System.String`
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EDIT: Haven't paid attention to ExecuteScalar. It does really return null if the field is absent in the return result. So use instead:
return (accountNumber == null) ? string.Empty : accountNumber.ToString()
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What is the “continue” keyword and how does it work in Java?
I saw this keyword for the first time and I was wondering if someone could explain to me what it does.
13 Answers
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Try catch statements in C
...tjmp and longjmp calls.
static jmp_buf s_jumpBuffer;
void Example() {
if (setjmp(s_jumpBuffer)) {
// The longjmp was executed and returned control here
printf("Exception happened here\n");
} else {
// Normal code execution starts here
Test();
}
}
void Test() {
// Rough eq...
JavaScript DOM remove element
I'm trying to test if a DOM element exists, and if it does exist delete it, and if it doesn't exist create it.
5 Answers
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How can I change the EditText text without triggering the Text Watcher?
... onTextChanged(CharSequence s, int start, int before, int count) {
if (myEditText.hasFocus()) {
// is only executed if the EditText was directly changed by the user
}
}
//...
});
Long answer
As an addition to the short answer:
In case myEditText already has th...
select * vs select column
If I just need 2/3 columns and I query SELECT * instead of providing those columns in select query, is there any performance degradation regarding more/less I/O or memory?
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Difference between window.location.href=window.location.href and window.location.reload()
What is the difference between JavaScript's
12 Answers
12
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Detect if an input has text in it using CSS — on a page I am visiting and do not control?
...nction adjustStyling (zEvent) {
var inpVal = zEvent.target.value;
if (inpVal && inpVal.replace (/^\s+|\s+$/g, "") )
zEvent.target.style.background = "lime";
else
zEvent.target.style.background = "inherit";
}
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How can I check if my python object is a number? [duplicate]
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Test if your variable is an instance of numbers.Number:
>>> import numbers
>>> import decimal
>>> [isinstance(x, numbers.Number) for x in (0, 0.0, 0j, decimal.Decimal(0))]
[True, True, True, True]
Thi...
UITableViewCell subview disappears when cell is selected
...oundColor;
[super setSelected:selected animated:animated];
if (selected){
self.yourView.backgroundColor = color;
}
}
-(void)setHighlighted:(BOOL)highlighted animated:(BOOL)animated{
UIColor *color = self.yourView.backgroundColor;
[super setHighlighted:hig...