使用 C# 获取数据库索引号时出错，显示 -1 [英] Error Getting Index Number on Database Using C#, Showing -1

问题描述

我用 C# 编写了一个脚本来使用 ComboBox 上的某个参数获取数据库上的索引号.

i have made a script in C# to get index number on database using someparameter on ComboBox.

private int category(string id) {
        int identity = 0;
        try
        {
            MySqlConnection conn = new MySqlConnection(connection.mysqlconnectionbuilder());
            conn.Open();
            MySqlCommand cmd = conn.CreateCommand();
            cmd.CommandText = "SELECT kategori.no FROM kategori WHERE kategori.kategori = @id";
            cmd.Parameters.AddWithValue("@id", id);
            cmd.CommandType = CommandType.Text;
            identity = cmd.ExecuteNonQuery();
            conn.Close();
        }
        catch (MySqlException msqe)
        {
            Console.Write(msqe.ToString());
        }
        return identity;
    }

我想根据名称示例获取索引号.好莱坞电影"--> ID : 2(在 DB 中)上面脚本的结果是-1.

I want to get Index number based on name example. "Hollywood Movie" --> ID : 2 (in DB) The result from above script is -1.

怎么解决?提前致谢.

推荐答案

如果要获取单个值，请使用 ExecuteScalar().

use ExecuteScalar() if you want to fetch single value.

identity = Convert.ToInt32(cmd.ExecuteScalar());

• ExecuteScalar方法(示例)

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