如何使 DataTable 可枚举？

发布于 2024-07-25 05:29:09 字数 878 浏览 3 评论 0原文

我无法在 DataTable 上使用 AsEnumerable()，我使用的是 C# 3，但我只是针对 2.0 框架（LINQ 功能由 LINQBridge）。有什么方法可以在不使用 Select() 的情况下使 DataTable 可枚举吗？

bool isExisting = (bdsAttachments.DataSource as DataTable).Select().Any(xxx => (string)dr["filename"] == filename);

更新：

我希望它看起来像这样：

bool isExisting = (bdsAttachments.DataSource as DataTable).AsEnumerable().Any(xxx => (string)dr["filename"] == filename);

我感觉到 DataTable 的 Select 方法返回一个副本，我想只使用 AsEnumerable，问题是我只是针对 2.0 框架 System. Data.DataSetExtensions 不可用

顺便说一句，我尝试了这个： http://cs.rthand.com/blogs/blog_with_righthand/archive/2006/01/15/284.aspx，但有编译错误。

原文

I cannot use AsEnumerable() on DataTable, I'm using C# 3 but I'm just targeting 2.0 framework (LINQ capability is courtesy of LINQBridge). Is there any way I can make DataTable enumerable without using Select() ?

bool isExisting = (bdsAttachments.DataSource as DataTable).Select().Any(xxx => (string)dr["filename"] == filename);

Update:

I wanted it to make it look like this:

bool isExisting = (bdsAttachments.DataSource as DataTable).AsEnumerable().Any(xxx => (string)dr["filename"] == filename);

I'm getting an inkling that the Select method of DataTable returns a copy, I'm thinking to just use AsEnumerable, the problem is I'm just targeting 2.0 framework, System.Data.DataSetExtensions is not available

BTW, i tried this: http://cs.rthand.com/blogs/blog_with_righthand/archive/2006/01/15/284.aspx, but has compilation errors.

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灰色世界里的红玫瑰 2024-08-01 05:29:09

    public static IEnumerable<DataRow> EnumerateRows(this DataTable table)
    {
        foreach (var row in table.Rows)
        {
            yield return row;
        }
    }

允许您拨打：

bool isExisting = (bdsAttachments.DataSource as DataTable).EnumerateRows().Any(dr => (string)dr["filename"] == filename);

    public static IEnumerable<DataRow> EnumerateRows(this DataTable table)
    {
        foreach (var row in table.Rows)
        {
            yield return row;
        }
    }

Allows you to call:

bool isExisting = (bdsAttachments.DataSource as DataTable).EnumerateRows().Any(dr => (string)dr["filename"] == filename);

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梦中的蝴蝶 2024-08-01 05:29:09

IEnumerable; rows = dataTable.AsEnumerable(); (System.Data.DataSetExtensions.dll)
IEnumerable; rows = dataTable.Rows.OfType(); (System.Core.dll)

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煮茶煮酒煮时光 2024-08-01 05:29:09

严格保持枚举器为 2.0：

public static IEnumerable<DataRow> getRows(DataTable table)
{
    foreach (DataRow row in table.Rows)
    {
        yield return row;
    }
}

然后使用 linqbridge 进行调用，如下所示：

bool isExisting = getRows(bdsAttachments.DataSource as DataTable).Any(row => (string)row["filename"] == filename);

Keeping your enumerator strictly 2.0:

public static IEnumerable<DataRow> getRows(DataTable table)
{
    foreach (DataRow row in table.Rows)
    {
        yield return row;
    }
}

Then call with linqbridge like this:

bool isExisting = getRows(bdsAttachments.DataSource as DataTable).Any(row => (string)row["filename"] == filename);

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一身骄傲 2024-08-01 05:29:09

您可以尝试将 DataTable 转换为 IEnumerable 并迭代

//your data exists as a DataTable
DataTable dt = (DataTable)bdsAttachments.DataSource;
foreach (DataRow row in dt)
{
    if (row["filename"] == filename)
        return row;
}

该集合：foreach 将迭代列表并搜索文件名（我假设您正在搜索具有该文件名的第一个 DataRow，而不是与文件名匹配的所有行）。

You can try casting the DataTable as IEnumerable and iterate over the set:

//your data exists as a DataTable
DataTable dt = (DataTable)bdsAttachments.DataSource;
foreach (DataRow row in dt)
{
    if (row["filename"] == filename)
        return row;
}

The foreach will iterate through the list and search of the filename (I assume you're searching for the first DataRow with that filename, not all rows that match the filename).

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