How to Handle 'Input string was not in a correct format' when Parsing Empty Strings in C#?

Exception Handling in Integer Parsing: "Input string was not in a correct format"

Encountering this error message when parsing an empty string using int.Parse() arises from the inherent constraint that the input string must adhere to a valid integer format.

Understanding the Error:

The error "Input string was not in a correct format" occurs because the string being parsed contains characters or symbols that are not recognized as part of a valid integer representation. An empty string, being devoid of any characters, naturally fails this validation.

Handling Empty Strings:

To gracefully handle empty strings during integer parsing, consider the following approaches:

1. Default to Zero on Empty Input:

If the desired behavior is to default to a value like 0 when the input string is empty, use the following code:

int i = string.IsNullOrEmpty(Textbox1.Text) ? 0 : int.Parse(Textbox1.Text);

This code checks if the input string (Textbox1.Text) is empty (using string.IsNullOrEmpty()) and assigns the default value of 0 if true. Otherwise, it parses the string to an integer.

2. Default to Zero on Any Invalid Input:

If the intention is to default to 0 for any invalid input, including empty strings, employ the following code:

int i;
if (!int.TryParse(Textbox1.Text, out i)) i = 0;

int.TryParse() attempts to parse the input string (Textbox1.Text) into an integer (i). If successful, i will hold the parsed value. If the string is empty or contains invalid characters, int.TryParse() returns false, and i is assigned the default value of 0.

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