限制字符串 剔除费需要字符然后将多余空格删除

for( int i=0; i<strCompletionDataList.GetLength(); i++)
            {
                if( !((strCompletionDataList[i]>=L'a' && strCompletionDataList[i]<=L'z')||(strCompletionDataList[i]>=L'A' && strCompletionDataList[i]<=L'Z') ||(strCompletionDataList[i]>=L'0' && strCompletionDataList[i]<=L'9') ||(strCompletionDataList[i]==L' ')))
                {
                    strCompletionDataList.Replace(strCompletionDataList[i],L' ');//将不合要求字符更替为空格
                }
                if( strCompletionDataList[i] == L' ' )
                {
                    spaceCount++;
                    if((i+1)<strCompletionDataList.GetLength())//判断未抵达最后一位
                    {
                        if( strCompletionDataList[i+1] != L' ' )//下一位不是空格
                        {
                            if(spaceCount > 1)
                            {
                                strCompletionDataList.Delete(i-(spaceCount-1),spaceCount-1);
                                i-=(spaceCount-1);
                                spaceCount = 0;                                 
                            }
                            else if (spaceCount = 1)
                                spaceCount = 0;
                        }
                    }
                    else if((i+1)>=strCompletionDataList.GetLength())//判断本位就是最后一位
                    {
                        strCompletionDataList.Delete(i-(spaceCount-1),spaceCount);
                        spaceCount = 0;
                    }
                }// end if( strCompletionDataList[i] == L' ' )
            }