asp.net SqlParameter如何根據條件有選擇的添加參數

 有時候寫sql語句的時候會根據方法傳進來的參數來判斷sql語句中where條件的參數，下面有個示例，大家可以參考下

      SqlParameter帶參數的增刪改查語句,可以防止注入.有時候寫sql語句的時候會根據方法傳進來的參數來判斷sql語句中where條件的參數.

一般方法

DAL層方法
代碼如下:
public UserInfo GetAll(UserInfo a)
{
string strSql = "select id,name,code,password from [tb].[dbo].[User] where 1=1";
strSql += " and [id]=@id";
strSql += " and [name]=@name";
strSql += " and [code]=@code";
strSql += " and [password]=@password";
SqlParameter[] parameters = {
new SqlParameter("@id", a.id)
new SqlParameter("@name", a.name)
new SqlParameter("@code", a.code),
new SqlParameter("@password", a.password)
};
SqlDataReader reader = SqlHelper.ExecuteReader(strSql, parameters);
UserInfo hc = new UserInfo();
while(reader.Read())
{
hc.id = reader.GetInt32(reader.GetOrdinal("id"));
hc.name = reader.GetString(reader.GetOrdinal("name"));
hc.code = reader.GetString(reader.GetOrdinal("code"));
hc.password = reader.GetString(reader.GetOrdinal("password"));
}
reader.Close();
return hc;
}
現在想根據集合UserInfo內屬性來添加SqlParameter參數

方法如下

DAL層方法
代碼如下:
public UserInfo GetALL(UserInfo a)
{
string strSql = "select id,name,code,password from [tb].[dbo].[User] where 1=1";
if (a.id>0) strSql += " and [id]=@id";
if (!string.IsNullOrEmpty(a.name)) strSql += " and [name]=@name";
if (!string.IsNullOrEmpty(a.code)) strSql += " and [code]=@code";
if (!string.IsNullOrEmpty(a.password)) strSql += " and [password]=@password";
List<SqlParameter> parametertemp = new List<SqlParameter>();
if (a.id > 0) parametertemp.Add(new SqlParameter("@id", a.id));
if (!string.IsNullOrEmpty(a.name)) parametertemp.Add(new SqlParameter("@name", a.name));
if (!string.IsNullOrEmpty(a.code)) parametertemp.Add(new SqlParameter("@code", a.code));
if (!string.IsNullOrEmpty(a.password)) parametertemp.Add(new SqlParameter("@password", a.password));
SqlParameter[] parameters = parametertemp.ToArray();//ToArray()方法將 List<T> 的元素復制到新數組中。

SqlDataReader reader = SqlHelper.ExecuteReader(strSql, parameters);
UserInfo hc = new UserInfo();
while (reader.Read())
{
hc.id = reader.GetInt32(reader.GetOrdinal("id"));
hc.name = reader.GetString(reader.GetOrdinal("name"));
hc.code = reader.GetString(reader.GetOrdinal("code"));
hc.password = reader.GetString(reader.GetOrdinal("password"));
}
reader.Close();
return hc;
}
DBUtility層SqlHelper
代碼如下:
public SqlDataReader ExecuteReader(string query, params SqlParameter[] parameters)
{
SqlConnString = GetConnect2();
SqlConnString.Open();
SqlCommand SqlCmd = new SqlCommand();
SqlCmd.Connection = SqlConnString;
SqlCmd.CommandText = query;
//SqlCmd.Parameters.AddRange(parameters);//AddRange()不能傳空參數組
//params 的意思就是允許傳空參數組
foreach (SqlParameter item in parameters)
{
SqlCmd.Parameters.Add(item);
}
SqlDataReader dr;
try
{
dr = SqlCmd.ExecuteReader(CommandBehavior.CloseConnection);
return dr;
}
catch (Exception ee)
{
SqlConnString.Close();
throw ee;
}
}