`DebuggerDisplayAttribute` in ADO.NET types

[Logerfo]

Description

As discussed in npgsql/npgsql#2687, some ADO.NET types could benefit from having a DebuggerDisplayAttribute. I could send a PR.

Which types should have it?

• Types that have a small handful number (preferably one) of "main" properties.

Which types should not have it?

• Types that overrides the ToString method, since the debugger uses it by default.

Pending questions

• Should we use a property pattern? Like the one described here and here.
  • Always? Only when displaying multiple properties? Never?
• Should the value be quoted? (,nq)
• Should we use nameof? I think so, but read dotnet/corefx#41386, which doesn't.

---

I'm putting up a suggestion list below. This list will be updated as new suggestions are made.

Type	Attribute Content
DbCommand	{CommandText}
DbConnection	State = {State}, ConnectionString = {ConnectionString}
DbParameter	ParameterName = {ParameterName}, Value = {Value}
DbParameterCollection	Count = {Count}
DbDataReader	{Command}

[YohDeadfall]

Speaking about debugging info, I would like to see "ParameterName = {ParameterName}, Value = {Value}" for the DbParameter type. The command type could expose the current state.

[Logerfo]

@YohDeadfall I have updated the description in order to include your suggestion for the DbParameter type. About the DbCommand type, I don't know what you mean. As far as I know, there is no State or similar property. It does exist for NpgsqlCommand, you might be mixing them up.

[YohDeadfall]

Sorry, I mean DbConnection.

[Logerfo]

OK, updated.

[vcsjones]

I wonder if there is any security guidance or concerns for using DebuggerDisplayAttribute on information that is sensitive. ConnectionString maybe contain a username and password.

[Logerfo]

@vcsjones I don't think there is any concern, as it probably would for ToString. If someone has access to the value displayed in the debugger through the attribute of a type, it's sure that they also have access to its members values, including private ones.