有时候写sql语句的时候会根据方法传进来的参数来判断sql语句中where条件的参数，下面有个示例，大家可以参考下

SqlParameter带参数的增删改查语句,可以防止注入.有时候写sql语句的时候会根据方法传进来的参数来判断sql语句中where条件的参数.

一般方法

DAL层方法

代码如下:

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;

}

现在想根据集合UserInfo内属性来添加SqlParameter参数

方法如下

DAL层方法

代码如下:

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()方法将 List<T> 的元素复制到新数组中。

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层SqlHelper

代码如下:

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()不能传空参数组

//params 的意思就是允许传空参数组

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;

}

}

<P>更多信息请查看<A href="c2021.aspx" target=_blank>IT技术专栏</A></P>