C# 从数组到数据表
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from array to datatable
提问by JUAN
ok i now it supose to be simple y have a multidimensional array, I try to fill my data table using the following code:
好的，我现在假设很简单，你有一个多维数组，我尝试使用以下代码填充我的数据表：
System.Data.DataTable _myDataTable =new System.Data.DataTable();
for (int j=0; j < ele; j++)
{
_myDataTable.Columns.Add();
for (int i = 0; i < caract+1; i++)
{
row[i]=(datar[j,i].ToString());
}
_myDataTable.Rows.Add(row);
}
My array name is datarbut the error I receive:
我的数组名称是datar但我收到的错误：
System.IndexOutOfRangeException: cant find column 1.
What am I doing wrong? By the way: I am using C#, asp.net, NOT Visual Studio.
我究竟做错了什么？顺便说一句：我使用的是 C#、asp.net，而不是 Visual Studio。
采纳答案by Filburt
As pointed out by chiffreyou actually have 3 problems: You will have to add all columns before you can start to add rows and you will have to create a DataRowbefore you can add it to your DataTable. Your third problem is your row-dimension counter caract+1which will yield an IndexOutOfRange exception.
正如chiffre所指出的，您实际上有 3 个问题：您必须先添加所有列，然后才能开始添加行，并且必须先创建一个，DataRow然后才能将其添加到DataTable. 你的第三个问题是你的行维计数器caract+1，它会产生一个 IndexOutOfRange 异常。
DataTable _myDataTable = new DataTable();
// create columns
for (int i = 0; i < ele; i++)
{
_myDataTable.Columns.Add();
}
for (int j = 0; j < caract; j++)
{
// create a DataRow using .NewRow()
DataRow row = _myDataTable.NewRow();
// iterate over all columns to fill the row
for (int i = 0; i < ele; i++)
{
row[i] = datar[i, j];
}
// add the current row to the DataTable
_myDataTable.Rows.Add(row);
}
回答by Alberto De Caro
Some issues:
一些问题：
- your code adds no column
- your code adds no row
- 您的代码不添加任何列
- 您的代码不添加任何行
Proceed step by step.
一步一步来。
Adding columns.
//using System.Data DataTable _myDataTable = new DataTable(); _myDataTable.Columns.Add(new DataColumn("Field_1")); _myDataTable.Columns.Add(new DataColumn("Field_2")); //... _myDataTable.Columns.Add(new DataColumn("Field_Ele"));Adding rows. You need to create a new Datarow from _myDataTable, populate it with data, add it to the table:
//assuming your data are stored in datar[,] String[,] datar = new String[max_i, max_j]; for (int i = 0; i < ele; i++) { DataRow r = _myDataTable.NewRow(); for (int j = 0; j < caract; j++) { //mind casting issues r[j] = datar[i, j]; } _myDataTable.rows.add(r); }
添加列。
//using System.Data DataTable _myDataTable = new DataTable(); _myDataTable.Columns.Add(new DataColumn("Field_1")); _myDataTable.Columns.Add(new DataColumn("Field_2")); //... _myDataTable.Columns.Add(new DataColumn("Field_Ele"));添加行。您需要从 _myDataTable 创建一个新的 Datarow，用数据填充它，将其添加到表中：
//assuming your data are stored in datar[,] String[,] datar = new String[max_i, max_j]; for (int i = 0; i < ele; i++) { DataRow r = _myDataTable.NewRow(); for (int j = 0; j < caract; j++) { //mind casting issues r[j] = datar[i, j]; } _myDataTable.rows.add(r); }
See herefor details.
有关详细信息，请参见此处。
回答by pmereles
public static DataSet MultidimensionalArrayToDataSet(string[,] input)
{
var dataSet = new DataSet();
var dataTable = dataSet.Tables.Add();
var iFila = input.GetLongLength(0);
var iCol = input.GetLongLength(1);
//Fila
for (var f = 1; f < iFila; f++)
{
var row = dataTable.Rows.Add();
//Columna
for (var c = 0; c < iCol; c++)
{
if (f == 1) dataTable.Columns.Add(input[0, c]);
row[c] = input[f, c];
}
}
return dataSet;
}
回答by RGH
Works if you have an array where the first row has the DataTable column name(s).
如果您有一个数组，其中第一行具有 DataTable 列名称，则该数组有效。
public static System.Data.DataTable ArrayToDataTable(Array array, bool headerQ=true)
{
if (array == null || array.GetLength(1) == 0 || array.GetLength(0) == 0) return null;
System.Data.DataTable dt = new System.Data.DataTable();
int dataRowStart = headerQ ? 1 : 0;
// create columns
for (int i = 1; i <= array.GetLength(1); i++)
{
var column = new DataColumn();
string value = array.GetValue(1, i) is System.String
? array.GetValue(1, i).ToString() : "Column" + i.ToString();
column.ColumnName = value;
dt.Columns.Add(column);
}
if (array.GetLength(0) == dataRowStart) return dt; //array has no data
//Note: the array is 1-indexed (not 0-indexed)
for (int i = dataRowStart + 1; i <= array.GetLength(0); i++)
{
// create a DataRow using .NewRow()
DataRow row = dt.NewRow();
// iterate over all columns to fill the row
for (int j = 1; j <= array.GetLength(1); j++)
{
row[j-1] = array.GetValue(i,j);
}
// add the current row to the DataTable
dt.Rows.Add(row);
}
return dt;
}
回答by Mustafa Demirhan
var dt = new DataTable();
var iFila = vals.GetLongLength(0);
var iCol = vals.GetLongLength(1);
for (var f = 1; f < iFila; f++)
{
var row = dt.Rows.Add();
for (var c = 1; c <= iCol; c++)
{
if (f == 1)
dt.Columns.Add(vals[1, c] != null
? vals[1, c].ToString()
: "");
row[vals[1, c].ToString()] = vals[f, c];
}
}
回答by Dr.sai
How about an extension method
扩展方法怎么样
static class HappyExtEnding
{
public static DataTable ToDataTable<T>(this T [] students)
{
if (students == null || students.Length == 0) return null;
DataTable table = new DataTable();
var student_tmp = students[0];
table.Columns.AddRange(student_tmp.GetType().GetFields().Select(field => new DataColumn(field.Name, field.FieldType)).ToArray());
int fieldCount = student_tmp.GetType().GetFields().Count();
students.All(student =>
{
table.Rows.Add(Enumerable.Range(0, fieldCount).Select(index => student.GetType().GetFields()[index].GetValue(student)).ToArray());
return true;
});
return table;
}
}
Usage
用法
Student[] students = {
new Student { Id = 1, Name = "Joe Rattz" ,Address="Sriram Apartments"},
new Student { Id = 6, Name = "Ulyses Hutchens" ,Address="Sriram Apartments"},
new Student { Id = 19, Name = "Bob Tanko" ,Address="Sriram Apartments"},
new Student { Id = 45, Name = "Erin Doutensal" ,Address="Sriram Apartments"},
new Student { Id = 1, Name = "Joe Rattz" ,Address="Sriram Apartments"},
new Student { Id = 12, Name = "Bob Mapplethorpe" ,Address="Sriram Apartments"},
new Student { Id = 17, Name = "Anthony Adams" ,Address="Sriram Apartments"},
new Student { Id = 32, Name = "Dignan Stephens Mark",Address="Sriram Apartments"},
new Student { Id = 1232, Name = "Dignan Stephens" ,Address="Sriram Apartments Henry Labamba Beligi"},
new Student { Id = 132, Name = "Neha Dhupia" ,Address="Sriram Apartments 123456"},
new Student { Id = 132, Name = "" ,Address="Sriram Apartments 123456"},
new Student { Id = 133, Name = "" ,Address="Sriram Apartments 123456"},
new Student { Id = 134, Name = "Neha Dhupia" ,Address=""},
new Student { Id = 134, Name = "Shradha Kapoor" ,Address="Mumbai"}
};
//ParallelQuery<int>
DataTable dtTmp = students.ToDataTable() ;
