使用 C# 对 MySQL 进行参数化查询 [英] Parameterized Query for MySQL with C#

问题描述

我有下面的代码(我已经包含了我认为所有相关的部分):

I have the code below (I've included what I believe are all relevant sections):

private String readCommand = "SELECT LEVEL FROM USERS WHERE VAL_1 = ? AND VAL_@ = ?;";
public bool read(string id)
{
    level = -1;
    MySqlCommand m = new MySqlCommand(readCommand);
    m.Parameters.Add(new MySqlParameter("", val1));
    m.Parameters.Add(new MySqlParameter("", val2));
    MySqlDataReader r = m.ExecuteReader();
    if (r.HasRows)
        level = Convert.ToInt32(r.GetValue(0).ToString());
    r.Close();
    return true;
}

当我运行这个时，我在添加第一个参数时得到一个 IndexOutOfBoundsException.我做错了什么?

When I run this, I get an IndexOutOfBoundsException on adding the first parameter. What have I done wrong?

推荐答案

试试这个:

private String readCommand = 
             "SELECT LEVEL FROM USERS WHERE VAL_1 = @param_val_1 AND VAL_2 = @param_val_2;";

public bool read(string id)
{
    level = -1;
    MySqlCommand m = new MySqlCommand(readCommand);
    m.Parameters.AddWithValue("@param_val_1", val1);
    m.Parameters.AddWithValue("@param_val_2", val2);
    level = Convert.ToInt32(m.ExecuteScalar());
    return true;
}

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