[英]Sorting a List<> using linq in C#
我想在Datagridview ColumnHeaderMouseClick下進行“排序”。 遞增或遞減應該是自動的,選擇的列值是自動的。
我瀏覽了許多網站並嘗試了一些選項,但我無法實現自己的目標。
private void lst_Install_Item_Main_ColumnHeaderMouseClick(object sender, DataGridViewCellMouseEventArgs e)
{
try
{
DataGridViewColumn newColumn = lst_Install_Item_Main.Columns[e.ColumnIndex];
List<test> temp = (List<test>)lst_Install_Item_Main.DataSource;
//var newList = temp.OrderBy(m => m.feet).ToList();
//var newList = temp.AsQueryable().OrderBy(m => m.feet).ToList();
temp.Sort((m1, m2) => m1.feet.CompareTo(m2.feet));
lst_Install_Item_Main.DataSource = temp;
lst_Install_Item_Main.Refresh();
}
catch (Exception ex)
{
MessageBox.Show("There was an error bringing sorting \n" + ex.Message, "Testing", MessageBoxButtons.OK, MessageBoxIcon.Error);
}
}
上面的代碼“排序”“腳”列上的列表,但是
我已經輸入了(1',21',123',5',10')之類的代碼以上代碼對列表進行了排序,例如>>(1',10',123',21',5')
但是我想要輸出>>(1',5',10',21',123')這樣的輸出嗎?
如何在此處實現升序或降序(我的意思是,當我第一次單擊時,它將進行升序;第二次單擊同一列時,則需要進行降序)
非常感謝您的建議幫助。
您必須將字符串轉換為整數值,因為字符串的順序不同(按字典順序, 10
在2
之前)。 此外,由於您的輸入包含'
字符,您必須首先使用String.Trim('\\'')
刪除它們。
temp.Sort((m1, m2) => Convert.ToInt32(m1.feet.Trim('\'')).CompareTo(Convert.ToInt(m2.feet.Trim('\''))));
另外,您也可以使用Linq-OrderBy
:
temp = temp.OrderBy(x => Convert.ToInt32(x.feet.Trim('\''))).ToList();
以及OrderByDescending
如果降序排列)。
您需要將feet
的值排序為整數。 為此,您首先需要刪除英尺符號( '
),然后將值解析為一個int
(臨時,該值仍存儲為字符串)。
這應該可以解決問題:
temp.Sort((m1, m2) => int.Parse(m1.feet.Replace("'", "")).CompareTo(int.Parse(m2.feet.Replace("'", ""))));
另外,我建議您不要在值中存儲英尺符號,而是在網格中顯示值時使用某種格式將其包括在內。 這樣,您每次需要使用值時就可以避免進行此類轉換和比較。
如果沒有負值,則要根據需要進行排序,您需要將值解析為數字或簡單地填充它們:
temp.Sort((m1, m2) => m1.feet.PadLeft(2).CompareTo(m2.feet.PadLeft(2)));
比較字符串"1"
, "5"
和"10"
將改為比較" 1"
, " 5"
和"10"
(注意,空格少於0
字符),使它們以正確的順序排序。
確保選擇足夠大的數字以覆蓋填充到最長的數字。
問題3已更新,為排序順序添加了觸發器
我建議您以這種方式使用ICoparer
public class TestComparer : IComparer<test>
{
bool isAscending;
public TestComparer(bool isAscendingOrder)
{
isAscending = isAscendingOrder;
}
int IComparer<test>.Compare(test a, test b)
{
int c1 = IntFromStr(a.feet);
int c2 = IntFromStr(b.feet);
int res;
res = (c1 > c2) ? 1 : (c1 < c2) ? -1 : 0;
return isAscending ? res : -res;
}
int IntFromStr(string s)
{
int result;
return (int.TryParse(s.Replace("'", ""), out result)) ? result : int.MaxValue;
}
}
此比較器會將無效的項目移到已排序列表的末尾,您也可以輕松更改自己的排序行為,如下所示
List < test > lst = new List<test>();
// It will be your property to Trigger value each time you click
// (sortOrderTrigger = !sortOrderTrigger)
bool sortOrderTrigger = true;
lst.Add(new test { feet = "1'" });
lst.Add(new test { feet = "21'" });
lst.Add(new test { feet = "123'" });
lst.Add(new test { feet = "5'" });
lst.Add(new test { feet = "10'" });
lst.Add(new test { feet = "15'" });
lst.Add(new test { feet = "jj'" });
lst.Add(new test { feet = "ff'" });
lst.Sort(new TestComparer(sortOrderTrigger));
感謝您的所有幫助和指導。 我已將要求固定如下,希望對我這樣的人有所幫助:)
1.創建的列表包含與列dataproperty相同的列。
public class sortList
{
public string Layer { get; set; }
public string mlenth { get; set; }
public string diameter { get; set; }
public string subtypecd { get; set; }
public string coatingtype { get; set; }
public string year { get; set; }
public string gisid { get; set; }
public string taxdistrict { get; set; }
public string lengthsource { get; set; }
public string shapelen { get; set; }
public string feet { get; set; }
public sortList()
{
this.Layer = ListSortDirection.Ascending.ToString();
this.mlenth = ListSortDirection.Ascending.ToString();
this.feet = ListSortDirection.Ascending.ToString();
this.diameter = ListSortDirection.Ascending.ToString();
this.subtypecd = ListSortDirection.Ascending.ToString();
this.coatingtype = ListSortDirection.Ascending.ToString();
this.year = ListSortDirection.Ascending.ToString();
this.gisid = ListSortDirection.Ascending.ToString();
this.taxdistrict = ListSortDirection.Ascending.ToString();
this.lengthsource = ListSortDirection.Ascending.ToString();
this.shapelen = ListSortDirection.Ascending.ToString();
}
}
2. ColumnHeaderMouseClick事件和順序函數上的書面代碼
private void lst_Install_Item_Main_ColumnHeaderMouseClick(object sender, DataGridViewCellMouseEventArgs e)
{
try
{
//Get Column which clicked
DataGridViewColumn newColumn = lst_Install_Item_Main.Columns[e.ColumnIndex];
//Get Values from DataGrid
List<test> temp = (List<test>)lst_Install_Item_Main.DataSource;
//Get the sorting order for that column
string orderby = GetOrder(newColumn.DataPropertyName);
if (orderby == ListSortDirection.Ascending.ToString()) //Ascending
{
if (newColumn.DataPropertyName == "feet") //Feet column sort with double value and required trim
{
temp = temp.OrderBy(x => Convert.ToDouble(x.feet.Trim('\''))).ToList();
}
else if (newColumn.DataPropertyName == "shapelen") //Shapelen column sort with double value and required trim
{
temp = temp.OrderBy(x => Convert.ToDouble(x.shapelen.Trim('\''))).ToList();
}
else ///other columns having string value only.
{
temp = temp.OrderBy(x => x.GetType().GetProperty(newColumn.DataPropertyName).GetValue(x, null)).ToList();
}
}
else // Descending
{
if (newColumn.DataPropertyName == "feet") //Feet column sort with double value and required trim
{
temp = temp.OrderByDescending(x => Convert.ToDouble(x.feet.Trim('\''))).ToList();
}
else if (newColumn.DataPropertyName == "shapelen") //Shapelen column sort with double value and required trim
{
temp = temp.OrderByDescending(x => Convert.ToDouble(x.shapelen.Trim('\''))).ToList();
}
else //other columns having string value only.
{
temp = temp.OrderByDescending(y => y.GetType().GetProperty(newColumn.DataPropertyName).GetValue(y, null)).ToList();
}
}
lst_Install_Item_Main.DataSource = temp;
lst_Install_Item_Main.Refresh();
}
catch (Exception ex)
{
MessageBox.Show("There was an error while sorting \n" + ex.Message, "Closeout Calculator", MessageBoxButtons.OK, MessageBoxIcon.Error);
}
}
private string GetOrder(string columnName)
{
//Store the each coulmn(Ascending/Descending) values to make it dynamic
string ord = sortOrder[0].GetType().GetProperty(columnName).GetValue(sortOrder[0], null).ToString();
if (ord == ListSortDirection.Ascending.ToString())
{
sortOrder[0].GetType().GetProperty(columnName).SetValue(sortOrder[0], ListSortDirection.Descending.ToString(), null);
}
else
{ sortOrder[0].GetType().GetProperty(columnName).SetValue(sortOrder[0], ListSortDirection.Ascending.ToString(), null); }
return ord;
}
3.排序列表初始化,並在構造方法中聲明obj。
Private List<sortList> sortOrder = new List<sortList>();
sortOrder.Add(new sortList());
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