日期:2014-05-18  浏览次数:21433 次

BindingSource.Filter 如何实现模糊查询
希望通过Filter属性进行过滤
BindingSource.Filter = "%p"; //ok
BindingSource.Filter = "%p%"; //ok
BindingSource.Filter = "%p%c%"; //wrong,提示表达式错误
如果希望进行第三种方式的模糊查询,应该怎么办?

------解决方案--------------------
刚才用Reflector看了下微软的实现,可以看出来的确不允许中间有通配符。
C# code
internal string AnalizePattern(string pat)
        {
            int length = pat.Length;
            char[] destination = new char[length + 1];
            pat.CopyTo(0, destination, 0, length);
            destination[length] = '\0';
            string str = null;
            char[] chArray2 = new char[length + 1];
            int num3 = 0;
            int num4 = 0;
            int index = 0;
            while (index < length)
            {
                if ((destination[index] == '*') || (destination[index] == '%'))
                {
                    while (((destination[index] == '*') || (destination[index] == '%')) && (index < length))
                    {
                        index++;
                    }
                    if (((index < length) && (num3 > 0)) || (num4 >= 2))
                    {
                        throw new Exception("ExprException.InvalidPattern(pat);");
                    }
                    num4++;
                }
                else if (destination[index] == '[')
                {
                    index++;
                    if (index >= length)
                    {
                        throw new Exception("ExprException.InvalidPattern(pat);");
                    }
                    chArray2[num3++] = destination[index++];
                    if (index >= length)
                    {
                        throw new Exception("ExprException.InvalidPattern(pat);");
                    }
                    if (destination[index] != ']')
                    {
                        throw new Exception("ExprException.InvalidPattern(pat);");
                    }
                    index++;
                }
                else
                {
                    chArray2[num3++] = destination[index];
                    index++;
                }
            }
            str = new string(chArray2, 0, num3);
            if (num4 == 0)
            {
                kind = 4;
                return str;
            }
            if (num3 > 0)
            {
                if ((destination[0] == '*') || (destination[0] == '%'))
                {
                    if ((destination[length - 1] == '*') || (destination[length - 1] == '%'))
                    {
                        kind = 3;
                        return str;
                    }
                    kind = 2;
                    return str;
                }
                kind = 1;
                return str;
            }
            kind = 5;
            return str;
        }