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Unable to cast object of type 'System.DBNull' to type 'System.String`
...
ExecuteScalar will return
null if there is no result set
otherwise the first column of the first row of the resultset, which may be DBNull.
If you know that the first column of the resultset is a string, then to cover all bases you need to check for both null and DBNull. Som...
What is the relationship between UIView's setNeedsLayout, layoutIfNeeded and layoutSubviews?
...yone give a definitive explanation on the relationship between UIView's setNeedsLayout , layoutIfNeeded and layoutSubviews methods? And an example implementation where all three would be used. Thanks.
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Correct format specifier to print pointer or address?
Which format specifier should I be using to print the address of a variable? I am confused between the below lot.
5 Answers...
Is there any async equivalent of Process.Start?
... true
};
process.Exited += (sender, args) =>
{
tcs.SetResult(process.ExitCode);
process.Dispose();
};
process.Start();
return tcs.Task;
}
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Changing names of parameterized tests
Is there a way to set my own custom test case names when using parameterized tests in JUnit4?
12 Answers
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In C#, how to check if a TCP port is available?
...if our port we would like to use
// in our TcpClient is occupied, we will set isAvailable to false.
IPGlobalProperties ipGlobalProperties = IPGlobalProperties.GetIPGlobalProperties();
TcpConnectionInformation[] tcpConnInfoArray = ipGlobalProperties.GetActiveTcpConnections();
foreach (TcpConnect...
Rails :dependent => :destroy VS :dependent => :delete_all
...ng their :destroy method
:nullify All associated objects' foreign keys are set to NULL without calling their save callbacks
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CSS3 Transparency + Gradient
RGBA is extremely fun, and so is -webkit-gradient , -moz-gradient , and uh... progid:DXImageTransform.Microsoft.gradient ... yeah. :)
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Maximum size of an Array in Javascript
... built a performance framework that manipulates and graphs millions of datasets, and even then, the javascript calculation latency was on order of tens of milliseconds. Unless you're worried about going over the array size limit, I don't think you have much to worry about.
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Specify pane percentage in tmuxinator project
...d be specified in the layout: line. But you are not limited to the five preset layouts (such as main-vertical). From the man page:
In addition, select-layout may be used to apply a previously used layout -
the list-windows command displays the layout of each window in a form
suitable for use with...