C# WinForms存储过程操作数据库的实例讲解

CREATE PROCEDURE sp_AddEmployee
    @Name NVARCHAR(50),
    @Age INT,
    @Email NVARCHAR(100),
    @NewID INT OUTPUT
AS
BEGIN
    INSERT INTO Employees (Name, Age, Email) 
    VALUES (@Name, @Age, @Email)
    
    SET @NewID = SCOPE_IDENTITY()
END

using System.Data;
using System.Data.SqlClient;

string connectionString = "Server=.;Database=YourDB;Integrated Security=True;";

public bool AddEmployee(string name, int age, string email, out int newId)
{
    using (SqlConnection conn = new SqlConnection(connectionString))
    {
        try
        {
            conn.Open();
            using (SqlCommand cmd = new SqlCommand("sp_AddEmployee", conn))
            {
                cmd.CommandType = CommandType.StoredProcedure;
                
                // 输入参数
                cmd.Parameters.Add("@Name", SqlDbType.NVarChar, 50).Value = name;
                cmd.Parameters.Add("@Age", SqlDbType.Int).Value = age;
                cmd.Parameters.Add("@Email", SqlDbType.NVarChar, 100).Value = email;
                
                // 输出参数
                SqlParameter outputParam = new SqlParameter("@NewID", SqlDbType.Int)
                {
                    Direction = ParameterDirection.Output
                };
                cmd.Parameters.Add(outputParam);

                cmd.ExecuteNonQuery();
                
                newId = (int)outputParam.Value;
                return true;
            }
        }
        catch (SqlException ex)
        {
            MessageBox.Show($"数据库错误: {ex.Message}");
            newId = -1;
            return false;
        }
    }
}

public DataTable GetEmployees(int minAge)
{
    DataTable dt = new DataTable();
    
    using (SqlConnection conn = new SqlConnection(connectionString))
    {
        using (SqlCommand cmd = new SqlCommand("sp_GetEmployees", conn))
        {
            cmd.CommandType = CommandType.StoredProcedure;
            cmd.Parameters.AddWithValue("@MinAge", minAge);

            SqlDataAdapter da = new SqlDataAdapter(cmd);
            da.Fill(dt);
        }
    }
    
    return dt;
}

public bool UpdateEmployeeTransaction(int id, string newName)
{
    using (SqlConnection conn = new SqlConnection(connectionString))
    {
        conn.Open();
        SqlTransaction transaction = conn.BeginTransaction();
        
        try
        {
            using (SqlCommand cmd = new SqlCommand("sp_UpdateEmployee", conn, transaction))
            {
                cmd.Parameters.AddWithValue("@ID", id);
                cmd.Parameters.AddWithValue("@NewName", newName);
                cmd.ExecuteNonQuery();
            }
            
            transaction.Commit();
            return true;
        }
        catch (Exception ex)
        {
            transaction.Rollback();
            MessageBox.Show($"操作失败: {ex.Message}");
            return false;
        }
    }
}

using (SqlConnection conn = new SqlConnection(...))
using (SqlCommand cmd = new SqlCommand(...))
{
    // 自动释放资源
}

try 
{
    // 数据库操作
}
catch (SqlException ex)
{
    // 处理数据库特有错误
    if (ex.Number == 547) // 外键约束错误
}
catch (Exception ex)
{
    // 常规异常处理
}