c# - 使用 SQL 准备语句在 C# 中绑定(bind)结果

Question

使用这个:

SqlConnection myConnection = new SqlConnection("Data Source=.\\SERVER;Initial Catalog=DB;Integrated Security=True;TrustServerCertificate=True;User Instance=False");
myConnection.Open();

SqlCommand myCommand = new SqlCommand("SELECT BusinessName FROM Businessess WHERE BusinessID = @Param2", myConnection);

SqlParameter myParam2 = new SqlParameter("@Param2", SqlDbType.Int, 4);
myParam2.Value = 1;
myCommand.Parameters.Add(myParam2);

MessageBox.Show(myCommand); //How do I bind results to show as string?

如何将准备好的语句的结果绑定(bind)到变量以便我可以操纵它们？

Answer 1

像这样尝试:

using (SqlConnection myConnection = new SqlConnection("Data Source=.\\SERVER;Initial Catalog=DB;Integrated Security=True;TrustServerCertificate=True;User Instance=False"))
using (SqlCommand myCommand = myConnection.CreateCommand())
{
    myConnection.Open();
    myCommand.CommandText = "SELECT BusinessName FROM Businessess WHERE BusinessID = @Param2";
    myCommand.Parameters.AddWithValue("@Param2", myParam2);
    using (SqlDataReader reader = myCommand.ExecuteReader())
    {
        if (reader.Read())
        {
            string businessName = reader.GetString(reader.GetOrdinal("BusinessName"));
            MessageBox.Show(businessName);
        }
        else
        {
            MessageBox.Show(string.Format("Sorry, no business found with id = {0}", myParam2));
        }
    }
}

注意事项:

• 一次性资源被包装在using语句中，以确保即使在异常情况下也能正确处理
• 传递给sql命令的参数的简化
• 调用命令上的 ExecuteReader 以检索允许您读取返回结果集的对象。