使用(LINQ/谓词)将数据表的所有列名获取到字符串数组中

I know we can easily do this by a simple loop, but I want to persue this LINQ/Predicate?

我知道我们可以通过一个简单的循环来实现这一点，但是我想要说服这个LINQ/谓词?

string[] columnNames = dt.Columns.?

or

string[] columnNames = from DataColumn dc in dt.Columns select dc.name;

4 个解决方案

#1

174

Try this (LINQ method syntax):

试试这个(LINQ方法语法):

string[] columnNames = dt.Columns.Cast<DataColumn>()
                                 .Select(x => x.ColumnName)
                                 .ToArray();

or in LINQ Query syntax:

或在LINQ查询语法中:

string[] columnNames = (from dc in dt.Columns.Cast<DataColumn>()
                        select dc.ColumnName).ToArray();

Cast is required, because Columns is of type DataColumnCollection which is a IEnumerable, not IEnumerable<DataColumn>. The other parts should be obvious.

强制转换是必需的，因为列是DataColumnCollection类型，它是一个IEnumerable，不是IEnumerable，而是。其他部分应该是显而易见的。

#2

Use

使用

var arrayNames = (from DataColumn x in dt.Columns
                  select x.ColumnName).ToArray();

#3

I'd suggest using such extension method:

我建议使用这种扩展方法:

public static class DataColumnCollectionExtensions
{
    public static IEnumerable<DataColumn> AsEnumerable(this DataColumnCollection source)
    {
        return source.Cast<DataColumn>();
    }
}

And therefore:

因此:

string[] columnNames = dataTable.Columns.AsEnumerable().Select(column => column.Name).ToArray();

You may also implement one more extension method for DataTable class to reduce code:

您还可以为DataTable类再实现一个扩展方法来减少代码:

public static class DataTableExtensions
{
    public static IEnumerable<DataColumn> GetColumns(this DataTable source)
    {
        return source.Columns.AsEnumerable();
    }
}

And use it as follows:

使用方法如下:

string[] columnNames = dataTable.GetColumns().Select(column => column.Name).ToArray();

#4

List<String> lsColumns = new List<string>();

if(dt.Rows.Count>0)
{
    var count = dt.Rows[0].Table.Columns.Count;

    for (int i = 0; i < count;i++ )
    {
        lsColumns.Add(Convert.ToString(dt.Rows[0][i]));
    }
}

#1

174