如何理解C#中的sqlparameter

Question

请问一下！
如何理解C#中的sqlparameter

Answer 1

表示 SqlCommand 的参数

Answer 2

对象而已，包括了sqlcommand需要的各个参数，可以通过带参构造函数实例化

Answer 3

 //通过 虚拟表 对数据表进行更新
        public bool Update(DataTable userTable)
        {
            SqlConnection con = null;
            try
            {
                con = new SqlConnection(ConnectionString);
                con.Open();                string sql = " update " + userTable.TableName + " set ";
               
                foreach(DataColumn dr in userTable.Columns)
                {
                    sql += dr.ColumnName + "=@" + dr.ColumnName + ",";
               
                }
                sql = sql.Substring(0, sql.Length - 1) + " where ";
                          SqlDataAdapter com = new SqlDataAdapter();
                 com.UpdateCommand = new SqlCommand(sql,con);
                                 foreach (DataColumn dc in userTable.Columns)
                 {
                     SqlParameter sp = new SqlParameter("@" + dc.ColumnName, dc.DataType);
                     sp.SourceColumn = dc.ColumnName;
                     com.UpdateCommand.Parameters.Add(sp);                  
                 }
                
                DataTable d = this.Select(" exec sp_pkeys "+userTable.TableName);                foreach(DataRow dr in d.Rows)
                {
                    sql += dr[3].ToString().Trim() + "=@" + dr[3].ToString().Trim() + " and ";
                   
                    //主键不更新
                    com.UpdateCommand.Parameters["@" + dr[3].ToString().Trim()].SourceVersion = DataRowVersion.Original;
                }
                sql = sql.Substring(0, sql.Length - 4);                                com.UpdateCommand.CommandText = sql;
 
                return Convert.ToBoolean(com.Update(userTable));
            }
            catch(Exception ex)
            {
                MessageBox.Show(ex.Message, "错误提示");
                return false;
            }
            finally
            {
                if(con.State== ConnectionState .Open)
                {
                    con.Close();
                }
            }
        }
     LZ 看下 这个 方法就知道了  这个方法是 通过 datatable  修改数据库表的