We see a piece of code that needs to dynamically transform the model in our work. When there are many data, the efficiency will be slow. Though C ා is case sensitive, it is fuzzy in Datarow, so C ා is very useful. The example Demo is as follows, and the second method is recommended.
Recommended writing:
public static List<T> DataTableToList2<T>(DataTable dt)
{
List<T> lists = new List<T>();
for (int i = 0; i < dt.Rows.Count; i++)
{
T t = Activator.CreateInstance<T>();
//Get all properties of the current T object
PropertyInfo[] propertys = t.GetType().GetProperties();
//Iterating out each attribute object through attribute set
foreach (PropertyInfo item in propertys)
{
int index = dt.Columns.IndexOf(item.Name);// Column names in datatable are not case sensitive,
if (index>=0)//dt.Columns.Contains(item.Name), it is faster to read the value with index
{
//Determine whether the single column value of the current DataTable is null
if (dt.Rows[i][index] != DBNull.Value)
//Assign the single column value of the current DataTable to the matching property, otherwise assign a null value
item.SetValue(t, (dt.Rows[i][index]), null);
else
item.SetValue(t, null, null);
}
}
lists.Add(t);
}
return lists;
}
Don't bother to write separately, just write the code:
public class TmpMode
{
public string AAA { get; set; }
public string BBB { get; set; }
public string c { get; set; }
public string AAA1 { get; set; }
public string BBB2 { get; set; }
public string AAA3 { get; set; }
public string BBB4 { get; set; }
public string AAA5 { get; set; }
public string BBB6 { get; set; }
public string AAA7 { get; set; }
public string BBB8 { get; set; }
public string AAA9 { get; set; }
public string BBB10 { get; set; }
public string BBB11 { get; set; }
public string AAA12 { get; set; }
public string BBB12 { get; set; }
public string AAA14 { get; set; }
public string BBB15 { get; set; }
}
public class DataTableTest
{
List<TmpMode> lstModes = new List<TmpMode>();
public void TestColumsNameIngore()
{
long first = 0, second = 0, three = 0;
DataTable t = new DataTable("mytable");
DataColumn col = new DataColumn("Aaa", System.Type.GetType("System.String"));
t.Columns.Add(col);
col = new DataColumn("Bbb", System.Type.GetType("System.String"));
t.Columns.Add(col);
col = new DataColumn("c", System.Type.GetType("System.String"));
t.Columns.Add(col);
col = new DataColumn("ddd", System.Type.GetType("System.String"));
t.Columns.Add(col);
for (int i = 0; i < 100; i++)
{
DataRow row = t.NewRow();
row["Aaa"] = "aaa" + i;
row["Bbb"] = "bbb" + i;
row["c"] = "c" + i;
t.Rows.Add(row);
}
StringBuilder str = new StringBuilder();
Stopwatch watch = new Stopwatch();
watch.Start();
lstModes = DataTableToList<TmpMode>(t);
foreach (var s in lstModes)
{
str.AppendLine(s.AAA + " " + s.BBB + " " + s.c);
}
watch.Stop();
Console.WriteLine("The first conversion:");
Console.WriteLine(str.ToString());
Console.WriteLine("Time:" + watch.ElapsedMilliseconds);
first = watch.ElapsedMilliseconds;
lstModes.Clear();
Console.WriteLine("Empty model:"+lstModes.Count);
watch.Reset();
watch.Start();
lstModes = DataTableToList2<TmpMode>(t);
str.Clear();
foreach (var s in lstModes)
{
str.AppendLine(s.AAA + " " + s.BBB + " " + s.c);
}
watch.Stop();
Console.WriteLine("The second conversion:");
Console.WriteLine(str.ToString());
Console.WriteLine("Time:" + watch.ElapsedMilliseconds);
second = watch.ElapsedMilliseconds;
lstModes.Clear();
Console.WriteLine("Empty model:" + lstModes.Count);
watch.Reset();
watch.Start();
lstModes = DataTableToList3<TmpMode>(t);
str.Clear();
foreach (var s in lstModes)
{
str.AppendLine(s.AAA + " " + s.BBB + " " + s.c);
}
watch.Stop();
Console.WriteLine("The Third Transformation:");
Console.WriteLine(str.ToString());
Console.WriteLine("Time:" + watch.ElapsedMilliseconds);
three = watch.ElapsedMilliseconds;
Console.WriteLine("contrast:" + first +" "+second+" "+three);
Console.ReadLine();
}
public static List<T> DataTableToList<T>(DataTable dt)
{
List<T> lists = new List<T>();
for (int i = 0; i < dt.Rows.Count; i++)
{
T t = Activator.CreateInstance<T>();
//Get all properties of the current T object
PropertyInfo[] propertys = t.GetType().GetProperties();
//Iterating out each attribute object through attribute set
foreach (PropertyInfo item in propertys)
{
#region == Original acquisition ==
//Loop out each column of DataTable
for (int j = 0; j < dt.Columns.Count; j++)
{
//Determine whether the current iterated property name is consistent with the column name of the iterated DataTable
if (item.Name.ToLower().Equals(dt.Columns[j].ColumnName.ToLower()))
{
//Determine whether the single column value of the current DataTable is null
if (dt.Rows[i][j] != DBNull.Value)
//Assign the single column value of the current DataTable to the matching property, otherwise assign a null value
item.SetValue(t, (dt.Rows[i][j]), null);
else
item.SetValue(t, null, null);
break;
}
}
#endregion
}
lists.Add(t);
}
return lists;
}
public static List<T> DataTableToList2<T>(DataTable dt)
{
List<T> lists = new List<T>();
for (int i = 0; i < dt.Rows.Count; i++)
{
T t = Activator.CreateInstance<T>();
//Get all properties of the current T object
PropertyInfo[] propertys = t.GetType().GetProperties();
//Iterating out each attribute object through attribute set
foreach (PropertyInfo item in propertys)
{
int index = dt.Columns.IndexOf(item.Name);// Column names in datatable are not case sensitive,
if (index>=0)//dt.Columns.Contains(item.Name), it is faster to read the value with index
{
//Determine whether the single column value of the current DataTable is null
if (dt.Rows[i][index] != DBNull.Value)
//Assign the single column value of the current DataTable to the matching property, otherwise assign a null value
item.SetValue(t, (dt.Rows[i][index]), null);
else
item.SetValue(t, null, null);
}
}
lists.Add(t);
}
return lists;
}
public static List<T> DataTableToList3<T>(DataTable dt)
{
List<T> lists = new List<T>();
for (int i = 0; i < dt.Rows.Count; i++)
{
T t = Activator.CreateInstance<T>();
//Get all properties of the current T object
PropertyInfo[] propertys = t.GetType().GetProperties();
//Iterating out each attribute object through attribute set
foreach (PropertyInfo item in propertys)
{
//Int index = DT. Columns. Indexof (item. Name); / / column names in datatable are not case sensitive,
if (dt.Columns.Contains(item.Name))//dt.Columns.Contains(item.Name), it is faster to read the value with index
{
//Determine whether the single column value of the current DataTable is null
if (dt.Rows[i][item.Name] != DBNull.Value)
//Assign the single column value of the current DataTable to the matching property, otherwise assign a null value
item.SetValue(t, (dt.Rows[i][item.Name]), null);
else
item.SetValue(t, null, null);
}
}
lists.Add(t);
}
return lists;
}
}Call test results:
DataTableTest test = new DataTableTest();
test.TestColumsNameIngore();! [when the data volume is large, the difference is more obvious] (http://img.blog.csdn.net/20180105174828511? Watermark / 2 / text / ahr0cdovl2jsb2cuy3nkbi5uzxqvcwlxaw5nbgk = / font / 5a6l5l2t / fontsize / 400 / fill / i0jbqkfcma = / resolve / 70 / gravity / Southeast)