The text box in question is involved in an if statement within my code, something to the effect of
所讨论的文本框包含在我代码中的if语句中,具有以下效果
if (textbox.text != "")
{
do this
}
I am curious if an empty text box will be considered an empty string or a null statement.
我很好奇一个空的文本框会被认为是一个空字符串还是一个空语句。
6 个解决方案
#1
24
Try to use IsNullOrWhiteSpace
, this will make sure of validating the whitespace too without having to trim it.
尝试使用isnullorespace,这将确保也验证该空白,而不必对其进行修剪。
if (!string.IsNullOrWhiteSpace(textbox.Text))
{
//code here
}
According to documentation string.IsNullOrWhiteSpace
evaluates to :-
根据文档字符串。IsNullOrWhiteSpace评估:-
return String.IsNullOrEmpty(value) || value.Trim().Length == 0;
String.IsNullOrEmpty
Indicates whether a specified string is null, empty, or consists only of white-space characters.
指示指定的字符串是否为空、空或仅由空白字符组成。
#2
4
In short it will be an empty string, but you could use the debugger and check that yourself.
简而言之,它将是一个空字符串,但是您可以使用调试器并自己进行检查。
However for best practice use IsNullOrEmpty
or IsNullOrWhiteSpace
但是对于最佳实践,使用IsNullOrEmpty或IsNullOrWhiteSpace
if (!string.IsNullOrEmpty(textbox.Text)) {
}
Alternatively:
另外:
if (!string.IsNullOrWhiteSpace(textbox.Text)) {
}
http://msdn.microsoft.com/en-us/library/system.string.isnullorwhitespace.aspx
http://msdn.microsoft.com/en-us/library/system.string.isnullorwhitespace.aspx
#3
2
It will be considered an empty string.
它将被认为是一个空字符串。
#4
2
It will be an empty string but better to check with this IsNullOrEmpty or IsNullOrWhiteSpace
它将是一个空字符串,但最好使用这个IsNullOrEmpty或IsNullOrWhiteSpace进行检查
if (!string.IsNullOrEmpty(textbox.text))
{
//do this
}
IsNullOrWhiteSpace is also take care of whitespace in input string. So if you don't want to execute the code for whitespace too then use second option.
IsNullOrWhiteSpace也会处理输入字符串中的空白。因此,如果您不想为空格执行代码,那么请使用第二个选项。
#5
-1
string search = txtSearch.Text.Trim() != "" ? txtSearch.Text.Trim() : "0";
#6
-3
if (textbox.text != "" || textbox.text != null)
如果(文本框。= " || textbox。文本! = null)
#1
24
Try to use IsNullOrWhiteSpace
, this will make sure of validating the whitespace too without having to trim it.
尝试使用isnullorespace,这将确保也验证该空白,而不必对其进行修剪。
if (!string.IsNullOrWhiteSpace(textbox.Text))
{
//code here
}
According to documentation string.IsNullOrWhiteSpace
evaluates to :-
根据文档字符串。IsNullOrWhiteSpace评估:-
return String.IsNullOrEmpty(value) || value.Trim().Length == 0;
String.IsNullOrEmpty
Indicates whether a specified string is null, empty, or consists only of white-space characters.
指示指定的字符串是否为空、空或仅由空白字符组成。
#2
4
In short it will be an empty string, but you could use the debugger and check that yourself.
简而言之,它将是一个空字符串,但是您可以使用调试器并自己进行检查。
However for best practice use IsNullOrEmpty
or IsNullOrWhiteSpace
但是对于最佳实践,使用IsNullOrEmpty或IsNullOrWhiteSpace
if (!string.IsNullOrEmpty(textbox.Text)) {
}
Alternatively:
另外:
if (!string.IsNullOrWhiteSpace(textbox.Text)) {
}
http://msdn.microsoft.com/en-us/library/system.string.isnullorwhitespace.aspx
http://msdn.microsoft.com/en-us/library/system.string.isnullorwhitespace.aspx
#3
2
It will be considered an empty string.
它将被认为是一个空字符串。
#4
2
It will be an empty string but better to check with this IsNullOrEmpty or IsNullOrWhiteSpace
它将是一个空字符串,但最好使用这个IsNullOrEmpty或IsNullOrWhiteSpace进行检查
if (!string.IsNullOrEmpty(textbox.text))
{
//do this
}
IsNullOrWhiteSpace is also take care of whitespace in input string. So if you don't want to execute the code for whitespace too then use second option.
IsNullOrWhiteSpace也会处理输入字符串中的空白。因此,如果您不想为空格执行代码,那么请使用第二个选项。
#5
-1
string search = txtSearch.Text.Trim() != "" ? txtSearch.Text.Trim() : "0";
#6
-3
if (textbox.text != "" || textbox.text != null)
如果(文本框。= " || textbox。文本! = null)