使用实体框架在SQL Server数据库中存储空字符串而不是Null

Question

There is a third party application table which allows Nulls for a few varchar columns. However, if a null is stored on those columns the application crashes. I cannot make any changes to either the application or the database.

To make matters a little more complicate the models have already been created using a designer and I only have access to a compiled dll that has all the company models.

I have created an ASP.NET MVC page which updates the table however if a column is left blank, a null is inserted in the database.

Is there any way to make sure that if a text box is left blank an empty string is stored in the database instead of null?

Answer 1

Add this to the property in your model:

[DisplayFormat(ConvertEmptyStringToNull = false)]

for example:

[DisplayFormat(ConvertEmptyStringToNull = false)]
public string ValToBeNotNullInDb {get;set;}

https://msdn.microsoft.com/en-us/library/system.componentmodel.dataannotations.displayformatattribute.convertemptystringtonull(v=vs.110).aspx