C# 清除 ASP.NET 中的文本框
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Clearing a TextBox in ASP.NET
提问by Hemant Kothiyal
I have webpage where there is textbox having some default value.
我有网页，其中有一些默认值的文本框。
I have to clear the value from text box. I have 2 options
我必须清除文本框中的值。我有2个选择
1. textbox.text="";
2. textbox.text.remove(0,length);
Here i would like to know which one should i use. Does it make any impact on page performance because there are many textbox placed in page.
在这里我想知道我应该使用哪个。因为页面中放置了许多文本框，所以它对页面性能有任何影响吗？
Thanks
谢谢
采纳答案by this. __curious_geek
The best way to do this is..
最好的方法是..
textbox.text = string.Empty;
Also remember that string type is immutable!
还要记住字符串类型是不可变的！
回答by Rex M
It makes no difference - do what is most readable for you and your colleagues.
这没什么区别 - 做对你和你的同事来说最易读的事情。
Many prefer to use string.Empty.
许多人更喜欢使用string.Empty.
回答by flesh
Presumably, you mean clear the value with javascript when a user clicks int the box? If so, it won't make any difference to performance.
据推测，您的意思是当用户单击框时使用 javascript 清除该值？如果是这样，它不会对性能产生任何影响。
I use jQuery in most pages, so I just hook up this function to clear default values onClick, using the ClientId of the textbox:
我在大多数页面中使用 jQuery，所以我只是连接这个函数来清除 onClick 的默认值，使用文本框的 ClientId：
$('#ctl00_TextBox').click(function() { $('#ctl00_TextBox').val('');
If you mean clear it in codebehind use this:
如果您的意思是在代码隐藏中清除它，请使用以下命令：
yourTextBox.Text = String.Empty;
回答by Sam Salisbury
The impact on performance will be minimal even with hundreds/thousands of calls, however
即使有数百/数千个调用，对性能的影响也很小，但是
textbox.text = "";
should in theory be very slightly quicker, since you're just assigning a new value rather than processing the string (as .Remove does)
理论上应该稍微快一点，因为您只是分配一个新值而不是处理字符串（如 .Remove 那样）
The best way to do this would be to do
最好的方法是这样做
textbox.text = String.Empty;
Update:if you're counting clock-cycles, String.Empty will actually execute faster as well, because it doesn't create a new object, whereas "" will create a new String object.
更新：如果你计算时钟周期， String.Empty 实际上也会执行得更快，因为它不会创建一个新对象，而 "" 将创建一个新的 String 对象。
However, you should really not be too concerned about this, there aren't many ways to set a string to empty that will cause performance issues! You should use whichever is the most readable...
但是，您真的不应该太担心这一点，没有很多方法可以将字符串设置为空会导致性能问题！你应该使用最易读的那个......
回答by John Saunders
- The performance difference between the two options will be too small to measure, most likely.
TextBox.Text = String.Empty;is a lot more readable. It clearly states what you're trying to do: "set the text property of this text box to an empty string".
- 很可能，这两个选项之间的性能差异太小而无法衡量。
TextBox.Text = String.Empty;更具可读性。它清楚地说明了您要执行的操作：“将此文本框的文本属性设置为空字符串”。
I recommend you go with the assignment, as it is both faster, and much more clear.
我建议你去做这个作业，因为它既快又清晰。
回答by venky
textbox.text="";
or
或者
foreach (var item in Page.Controls)
{
if (item is TextBox)
{
((TextBox)item).Text = "";
}
}
