復制代碼 代碼如下:

if(id>0 && string.IsNullOrEmpty(name))
{
command.CommandText = "select * from t1 where id=?";
command.Parameters.Add(id);
}
if(id<=0 && !string.IsNullOrEmpty(name))
{
command.CommandText = "select * from t1 where name=?";
command.Parameters.Add(name);
}
if(id<=0 && !string.IsNullOrEmpty(name))
{
command.CommandText = "select * from t1 where id=? and name=?";
command.Parameters.Add(id);
command.Parameters.Add(name);
}

復制代碼 代碼如下:

string sql ="select * from t1 where 1=1";
if(id != null)
{
sql += " and id=?";
addParameterValue(cmd,id);
}
if(!string.IsNullOrEmpty(name))
{
sql += " and name=?";
addParameterValue(cmd,name);
}
command.CommandText = sql;

復制代碼 代碼如下:

if(id>0 && string.IsNullOrEmpty(name))

復制代碼 代碼如下:

if(id != null)

復制代碼 代碼如下:

DbParameter p = cmd.CreateParameter();
p.ParameterName = "@XXX";
p.Value = TTT;
cmd.Parameters.Add(p);