internal static async Task <Resp> UpdatePartial <TType>(this IDbConnection con, string tableName,
Expression <Func <TType, object> > update, Expression <Func <TType, bool> > where, object mo)
//where TType : BaseMo<IdType>
{
if (string.IsNullOrEmpty(tableName))
{
tableName = typeof(TType).Name;
}
var visitor = new SqlExpressionVisitor();
var updateSql = GetVisitExpressSql(visitor, update, SqlVistorType.Update);
var whereSql = GetVisitExpressSql(visitor, where, SqlVistorType.Where);
var sql = string.Concat("UPDATE ", tableName, " SET ", updateSql, whereSql);
var paras = GetExecuteParas(mo, visitor);
var row = await con.ExecuteAsync(sql, paras);
return(row > 0 ? new Resp() : new Resp().WithResp(RespTypes.OperateFailed, "更新失败!"));
}
/// <summary>
/// 处理where条件表达式，如果表达式为空，默认使用Id
/// </summary>
/// <param name="visitor"></param>
/// <param name="exp"></param>
/// <param name="visType"></param>
private static string GetVisitExpressSql(SqlExpressionVisitor visitor, Expression exp, SqlVistorType visType)
{
if (visType == SqlVistorType.Update)
{
var updateFlag = new SqlVistorFlag(SqlVistorType.Update);
visitor.Visit(exp, updateFlag);
return(updateFlag.sql);
}
string sql;
if (exp == null)
{
throw new ArgumentNullException("whereExp", "where表达式不能为空！");
}
else
{
var whereFlag = new SqlVistorFlag(SqlVistorType.Where);
visitor.Visit(exp, whereFlag);
sql = string.Concat(" WHERE ", whereFlag.sql);
}
return(sql);
}