i am receiving this problem
Conversion from type 'DBNull' to type 'String' is not valid.
Line 501: hfSupEmail.Value = dt.Rows(0)("SupEmail")
i am very new to this, i am not really sure what is the exact problem could someone guide me?
Many thanks
The quick and dirty fix:
hfSupEmail.Value = dt.Rows(0)("SupEmail").ToString()
or for C#:
hfsupEmail.Value = dt.Rows[0]["SupEmail"].ToString();
This works very well when your eventual target and the source data are already strings. This is because any extra .ToString() call for something that's already a string will generally be optimized by the jitter into a no-op, and if it's NULL the resulting DBNull.Value.ToString() expression produces the empty string you want.
However, if you're working with non-string types, you may end up doing significant extra work, especially with something like a DateTime or numeric value where you want specific formatting. Remember, internationalization concerns mean parsing and composing date and number values are actually surprisingly expensive operations; doing "extra" work to avoid those operations is often more than worth it.
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