C# 如何为 Html.TextBoxFor( ... ) 文本框设置默认值？
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How do you set a default value for a Html.TextBoxFor( ... ) text box?
提问by Alex
I know that you can create a textbox using ASP.NET that will automatically be filled with whatever the value in the model is by using
我知道您可以使用 ASP.NET 创建一个文本框，该文本框将通过使用模型中的任何值自动填充
<%: Html.TextBoxFor(model => model.FirstName, new { id = "FirstName", placeholder = "[First Name]" }) %>
Is there a way to give it a default value if model.FirstNameis null?
如果model.FirstName为空，有没有办法给它一个默认值？
I've tried adding a value attribute, but that didn't work.
我试过添加一个 value 属性，但这没有用。
I also can't pass in a model with that value included, because it will affect other areas of the form.
我也无法传入包含该值的模型，因为它会影响表单的其他区域。
采纳答案by Mario Sannum
You could change the model property to return a default value if it's null (or setting default values when creating the model) or you can use the Html.TextBoxhelper instead of Html.TextBoxFor:
如果模型属性为 null（或在创建模型时设置默认值），您可以更改模型属性以返回默认值，或者您可以使用Html.TextBox帮助程序而不是Html.TextBoxFor：
<%: Html.TextBox("FirstName", Model.FirstName ?? "The default value", new { id = "FirstName", placeholder = "[First Name]" }) %>
or use the value-attribute:
或使用值属性：
<%: Html.TextBoxFor(model => model.FirstName, new { @Value = "The default value", id = "FirstName", placeholder = "[First Name]" }) %>
回答by chris
Would something like a watermark work for what you're trying to accomplish?
像水印这样的东西是否适合您要完成的任务？
There are a number of different implementation for jquery - thislooks like it would work, and there is an option to use the title attribute for the watermark, which could be part of your model.
jquery 有许多不同的实现 -这看起来可以工作，并且有一个选项可以使用水印的标题属性，这可能是您模型的一部分。
