C#字符串处理、字符串转数组、数组转字符串
一、指示指定的String对象是空引用还是Empty字符串。(如果value参数为空引用或空字符串 (""),则为true;否则为 false。)
if (!string.IsNullOrEmpty("字符串"))
{}
二、定义字符串
string str= string.Empty;
三、IDataReader中读取数据空字符串处理
if (reader["MessageHistoryID"] == DBNull.Value)
{
model.IsRead = true;
}
if(ds.Tables[0].Rows[0]["ID"].ToString()!="")
{
model.ID=int.Parse(ds.Tables[0].Rows[0]["ID"].ToString());
}
四、List<int>集合转换为字符串
List<int> list = new List<int>();
list.Add(100);
list.Add(90);
list.Add(60);
list.Add(80);
list.Add(10);
list.Add(40);
list.Add(20);
list.Add(10);
list.Add(50);
list.Add(50);
///所见即所得
string strArr = string.Join(",", list.ToArray());
///升序
string strArrOrderBy = string.Join(",", list.ToArray().OrderBy(o => o));
///降序
string strArrOrderByDesc = string.Join(",", list.ToArray().OrderByDescending(o => o));
///去除重复
string strArrDistinct = string.Join(",", list.ToArray().Distinct());
///排序、去除重复
string strArrOrderByDescDistinct = string.Join(",", list.ToArray().OrderByDescending(o => o).Distinct());
strArr输出结果:100,90,60,80,10,40,20,10,50,50
strArrOrderBy输出结果:10,10,20,40,50,50,60,80,90,100
strArrOrderByDesc输出结果:100,90,80,60,50,50,40,20,10,10
strArrDistinct输出结果:100,90,60,80,10,40,20,50
strArrOrderByDescDistinct输出结果:100,90,80,60,50,40,20,10
五、字符串转数组
#region 字符串转数组
List<int> listArr = new List<int>();
string str = "gfedfdasfdasferwq431241324321ablk";
var query = from s in str orderby s select s;
char[] sortStr = query.ToArray();
string strRes = new string(sortStr);
Label1.Text = strRes;
#endregion
#region 字符串转数组
List<int> listStrArr = new List<int>();
string strapp = "19,92,63,45,51,62,47,85,9,10";
string[] strtemp = strapp.Split(',');
foreach (string item in strtemp)
{
listStrArr.Add(Convert.ToInt32(item));
}
Label1.Text = string.Join(",", listStrArr.ToArray());
var num = "1,2,3,4,5,6".Split(',').Select(v => Convert.ToInt32(v)).ToArray();
string aa = num[0].ToString();
string bb = num[1].ToString();
#endregion
六、List<T>.Contains方法(确定某元素是否在 List<T> 中)
List<int> idList = new List<int>();
while (reader.Read())
{
Message model = Message(reader);
if (!idList.Contains(model.MessageID))
idList.Add(model.MessageID);
list.Add(model);
}
七、过滤特殊字符
public string DelQuota(string str)
{
string result = str;
string[] strQuota = { "~", "!", "@", "#", "$", "%", "^", "&", "*", "(", ")", "`", ";", "'", ",", ".", "/", ":", "/,", "<", ">", "?" };
for (int i = 0; i < strQuota.Length; i++)
{
if (result.IndexOf(strQuota[i]) > -1)
result = result.Replace(strQuota[i], "");
}
return result;
}