无法将参数值从Int64转换为Byte []

Question

I am getting the error:

Failed to convert parameter value from a Int64 to a Byte[].

Here is what I am doing...

I have a table in my database with the column:

sessionid | binary(32) | null

When I assign to it, I do this:

user.LastActivityDate = DateTime.Now;
user.SessionId = user.LastActivityDate.ToBinary();

SessionId is an inherited property from an interface:

long? SessionId { get; set; }

And here it is being accessed in my User class:

[SettingsAllowAnonymous(false), CustomProviderData("SessionId;string")]
public long? SessionId { get { return base["SessionId"] as long?; } set { base["SessionId"] = value; } }

In my custom profile provider, the following command assigns the value:

sqlCommand.Parameters.Add("sessionid", SqlDbType.Binary, 32).Value = settingsPropertyValue.PropertyValue;

When the "sqlCommand.ExecuteNonQuery()" command executes an update stored procedure is executed with the parameter:

@sessionid binary(32)

And the result is the error:

"Failed to convert parameter value from a Int64 to a Byte[]."

I have tried:

1. ... = Convert.ToByte(settingsPropertyValue.PropertyValue);
2. ... = Convert.ToInt64(settingsPropertyValue.PropertyValue);

Any ideas? Thanks.

Answer 1

SqlDbType.Binary is not correct (when you add the parameter) -- that's for extended binary data of arbitrary length. You want to just represent it as a 64-bit integer, which is SqlDbType.BigInt .

By the way, why are you doing this in the first place? SQL has a date-time type; you can just store it like that.

(You could go about it in the opposite, perverse way and instead convert the long to an eight-byte array and pass that, but there's no conceivable reason you would want to store it in that manner.)

Answer 2

ToBinary doesn't do what you think it does.

The DateTime.ToBinary method returns a long value, not a byte array.

What are you trying to do?

If you're trying to store the datetime, you should just use a DataTime column.

If you actually want a byte array, please provide more details.