空NSDatePicker [英] empty NSDatePicker

问题描述

嗨 是否可以使用NSDatePicker表示一个nil对象? -/-/-之类的东西.

Hi Is it possible to have a NSDatePicker representing a nil object? Something like -/-/- or any other way.

谢谢， 拉杜

推荐答案

简短答案:否

NSDatePicker只会忽略无效的日期和nil.
例如，这不会更新NSDatePicker，原来的值保持不变:

NSDatePicker simply ignores invalid dates and nil.
For example, this does not update the NSDatePicker, the old value remains:

[datePicker setDateValue:nil];

仅解决方案:检测nil并执行特定操作:

Only solution: Detect nil and do something specific:

if(date == nil) {

    // Set Specific Date
    NSDateFormatter *dateFormat = [[NSDateFormatter alloc] init];
    [dateFormat setDateFormat:@"yyyyMMdd"];
    NSDate *nilDate = [dateFormat dateFromString:@"20000101"];  
    [datePicker setDateValue:nilDate];

    // Or Disable
    [datePicker setEnabled:FALSE];

} else {

    // Update Date
    [datePicker setDateValue:date];

}

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