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c#datetimetostringnullable
Ilaria
Ilaria

Reputation: 187

Method 'ToString' of DateTime? has 0 parameter(s)but is invoked with 1 argument(s)

My ProcessDate type is DateTime? when i use ToString it is showing that exception. 

dfCalPlanDate.Text = concreteCalPlan.ProcessDate.ToString("d");

Thank you for your interested.

Upvotes: 4

Views: 3256

Answers (2)

Heinzi
Heinzi

Reputation: 172380

Simple: Nullable<T> (and, thus, Nullable<DateTime>, aka DateTime?) does not have a method ToString(String).

You probably wanted to invoke DateTime.ToString(String). To do this in a null-safe way, you can use C# 6's null-conditional operator ?.:

dfCalPlanDate.Text = concreteCalPlan.ProcessDate?.ToString("d");

which is a concise way of writing:

var date = concreteCalPlan.ProcessDate;
dfCalPlanDate.Text = (date == null ? null : date.Value.ToString("d"));

Note that this will yield null if ProcessDate is null. You can append the null-coalescing operator ?? if you need another result in that case:

dfCalPlanDate.Text = concreteCalPlan.ProcessDate?.ToString("d") ?? "no date set";

Upvotes: 13

Palle Due
Palle Due

Reputation: 6292

ProcessDate is not a DateTime. ProcessDate.Value is. You need to do:

dfCalPlanDate.Text = concreteCalPlan.ProcessDate.Value.ToString("d");

Remember to check if the DateTime? has a value first.

Upvotes: 3

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