c# - 解决连接字符串问题

Question

我有一个 SQL 连接字符串，它给了我一个错误。
错误是:
System.ArgumentException: '不支持关键字:'allowuservariables'。'

using (SqlConnection con = new SqlConnection())
        {
            con.ConnectionString = "server=localhost;user id=root;database=Phone_diary_project1;allowuservariables=True;persistsecurityinfo=True";
            con.Open();
            using (SqlCommand com = con.CreateCommand())
            {
                com.CommandText = "insert into diary(First," +
                    "Last," +
                    "Mobile," +
                    "Email," +
                    "" +
                    "Category) " +
                    "values(" +
                    "@prm1," +
                    "@prm2," +
                    "@prm3," +
                    "@prm4," +
                    "@prm5) ";
                com.Parameters.Add("@prm1", SqlDbType.VarChar, 50).Value = textBox1.Text;
                com.Parameters.Add("@prm2", SqlDbType.VarChar, 50).Value = textBox2.Text;
                com.Parameters.Add("@prm3", SqlDbType.Int).Value = textBox3.Text;
                com.Parameters.Add("@prm4", SqlDbType.VarChar, 50).Value = textBox4.Text;
                com.Parameters.Add("@prm5", SqlDbType.VarChar, 50).Value = comboBox1.Text;
                com.ExecuteNonQuery();
            }
            con.Close();
        }

Answer 1

AllowUserVariables是 MySQL 连接字符串选项:https://mysqlconnector.net/connection-options/#AllowUserVariables . (您还标记了这个问题 mysql 。)
但是，您的代码正在使用 SqlConnection ，这仅用于连接到 Microsoft SQL Server。安装 MySqlConnector从 NuGet 并更改您的代码以使用 MySqlConnection , MySqlCommand , MySqlDbType ， 等等。
顺便说一句，你实际上并不需要 AllowUserVariables对于此代码示例； MySQL 语句中始终允许使用命令参数。