c# error when connect to mysql "Object cannot be cast from DBNull to other types" (mariadb 10.3)

Question

c# error when connect to mysql "Object cannot be cast from DBNull to other types" (mariadb 10.3)

kriangkrai kongsamlee 5

Object cannot be cast from DBNull to other types" (mariadb 10.3)

Jack J Jun 25,301 Reputation points

2023-03-27T08:29:42.3866667+00:00

@kriangkrai kongsamlee, Welcome to Microsoft Q&A, could you provide some c# code with me? I will have a test for it.
GeethaThatipatri-MSFT 29,567 Reputation points Microsoft Employee Moderator

2023-03-30T14:58:08.95+00:00

@kriangkrai kongsamlee are you still facing the issue? can you please provide more information on the error?

Regards

Geetha
M R 0 Reputation points

2025-04-29T09:13:55.9166667+00:00

Hi, I have the same problem. When my C# code wants to make a SQL-connection I the error mentioned:
System.InvalidCastException: 'Object cannot be cast from DBNull to other types.'
Source: "mscorlib"
The problem started when I got a new laptop. Unfortunately the old one is wiped already.
I am not sure if this has anything to do with a column (like in the answer).

What can I do?

2 answers

Your answer

Jack J Jun 25,301 Reputation points

2023-03-27T08:29:42.3866667+00:00

@kriangkrai kongsamlee, Welcome to Microsoft Q&A, could you provide some c# code with me? I will have a test for it.
GeethaThatipatri-MSFT 29,567 Reputation points Microsoft Employee Moderator

2023-03-30T14:58:08.95+00:00

@kriangkrai kongsamlee are you still facing the issue? can you please provide more information on the error?

Regards

Geetha
M R 0 Reputation points

2025-04-29T09:13:55.9166667+00:00

Hi, I have the same problem. When my C# code wants to make a SQL-connection I the error mentioned:
System.InvalidCastException: 'Object cannot be cast from DBNull to other types.'
Source: "mscorlib"
The problem started when I got a new laptop. Unfortunately the old one is wiped already.
I am not sure if this has anything to do with a column (like in the answer).

What can I do?

Answer 1

Bruce (SqlWork.com) 79,106 Volunteer Moderator

That is correct. when a column value is null, the object DBNull is returned rather than a typed value. You must first test that the column value is not null via the api before accessing as the desired type.

Answer 2

SurferOnWww 4,821

If you use the Connector/NET (i.e., MySql.Data), try using the MySqlConnector instead of MySql.Data.

References:

MySQL Connector fails to connect to MariaDB 10.10.2

MySqlConnection.Open() System.InvalidCastException: Object cannot be cast from DBNull to other types

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c# error when connect to mysql "Object cannot be cast from DBNull to other types" (mariadb 10.3)

2 answers

Your answer