Conversion failed when converting the varchar to data type int: SQL

Question

I am creating a web app in asp.net mvc I have a query which looks like below

using (SqlConnection conn = new SqlConnection(_connStr))
{
    conn.Open();

    var p = new DynamicParameters();
    p.Add("@SP_RoleId", "7,8,9", dbType: DbType.String, direction: ParameterDirection.Input);
    p.Add("@SP_UserId", userId, dbType: DbType.Int32, direction: ParameterDirection.Input);

    var obj = conn.Query<PendingKmsRequest>(sql: "SELECT [f].[id] AS [FileId],[fvr].[Id] AS [RequestId], [au].[Name]"
                        + ", [fvr].[RequestByUserId], [fvr].[FromDate], [fvr].[ToDate],[f].[Title], [fvr].[Status], [fvr].[StatusRemarks]"
                        + "FROM [dbo].[File] AS[f]"
                        + "INNER JOIN [dbo].[FileViewRequest] AS [fvr] ON [f].[CurrentFileVersionId] = [fvr].[FileVersionId]"
                        + "INNER JOIN [Access].[User] AS [au] ON [fvr].[RequestByUserId] = [au].[Id]"
                        + "WHERE ([fvr].[Status] = 'P' OR ([fvr].[Status] = 'A' AND [fvr].[StatusByUserId] = @SP_UserId AND GETDATE() BETWEEN [fvr].[FromDate] AND [fvr].[ToDate]))"
                        + "AND (SELECT 1 FROM [Access].[UserRoleMap] WHERE UserId=@SP_UserId AND RoleId IN(@SP_RoleId)) = 1", param: p, commandType: CommandType.Text);

    if (obj != null && obj.Count() > 0)
        return obj.ToList();
    else
        return new List<PendingKmsRequest>();
}

NOTE: Role id is always like (7,8,9) and it is int column in the database.

I get this conversion error on this line of code:

 WHERE UserId = @SP_UserId AND RoleId IN (@SP_RoleId))

This is the error:

Conversion failed when converting the nvarchar value '7,9,10' to data type int.

How can I prevent this error?

Answer 1

The following line in your question code:

p.Add("@SP_RoleId", "7,8,9", dbType: DbType.String, direction: ParameterDirection.Input);

The value "7,8,9" is string and parameter type DbType.String is string as well.

But, you said this is int in your database. This is mismatch.

Further, your query:

WHERE UserId = @SP_UserId AND RoleId IN (@SP_RoleId))

The query is using IN clause.

Dapper can convert your value for IN clause if pass in an IEnumerable.

Change the line of code as below:

p.Add("@SP_RoleId", new[] {7,8,9}, dbType: DbType.Int32, direction: ParameterDirection.Input);