如何在powershell中循环数据集？

I am trying a "very" simple task to output values of each rows from a DataSet :

我正在尝试从“DataSet”输出每行的“非常”简单任务：

for ($i=0;$i -le $ds.Tables[1].Rows.Count;$i++)
{
  Write-Host 'value is : ' + $i + ' ' + $ds.Tables[1].Rows[$i][0]
}

gives output ...

给出输出......

value is :  +0+ +System.Data.DataSet.Tables[1].Rows[0][0] 
value is :  +1+ +System.Data.DataSet.Tables[1].Rows[1][0] 
value is :  +2+ +System.Data.DataSet.Tables[1].Rows[2][0] 
value is :  +3+ +System.Data.DataSet.Tables[1].Rows[3][0] 
value is :  +4+ +System.Data.DataSet.Tables[1].Rows[4][0] 
value is :  +5+ +System.Data.DataSet.Tables[1].Rows[5][0] 
value is :  +6+ +System.Data.DataSet.Tables[1].Rows[6][0]

How do i get the actual value from the column?

如何从列中获取实际值？

3 个解决方案

#1

The PowerShell string evaluation is calling ToString() on the DataSet. In order to evaluate any properties (or method calls), you have to force evaluation by enclosing the expression in $()

PowerShell字符串评估在DataSet上调用ToString（）。为了评估任何属性（或方法调用），您必须通过将表达式括在$（）中来强制求值

for($i=0;$i -lt $ds.Tables[1].Rows.Count;$i++)
{ 
  write-host "value is : $i $($ds.Tables[1].Rows[$i][0])"
}

Additionally foreach allows you to iterate through a collection or array without needing to figure out the length.

另外foreach允许您遍历集合或数组，而无需计算长度。

Rewritten (and edited for compile) -

重写（并编辑编译） -

foreach ($Row in $ds.Tables[1].Rows)
{ 
  write-host "value is : $($Row[0])"
}

#2

Here's a practical example (build a dataset from your current location):

这是一个实际示例（从您当前位置构建数据集）：

$ds = new-object System.Data.DataSet
$ds.Tables.Add("tblTest")
[void]$ds.Tables["tblTest"].Columns.Add("Name",[string])
[void]$ds.Tables["tblTest"].Columns.Add("Path",[string])

dir | foreach {
    $dr = $ds.Tables["tblTest"].NewRow()
    $dr["Name"] = $_.name
    $dr["Path"] = $_.fullname
    $ds.Tables["tblTest"].Rows.Add($dr)
}


$ds.Tables["tblTest"]

$ds.Tables["tblTest"] is an object that you can manipulate just like any other Powershell object:

$ ds.Tables [“tblTest”]是一个可以像任何其他Powershell对象一样操作的对象：

$ds.Tables["tblTest"] | foreach {
    write-host 'Name value is : $_.name
    write-host 'Path value is : $_.path
}

#3

The parser is having trouble concatenating your string. Try this:

解析器在连接字符串时遇到问题。尝试这个：

write-host 'value is : '$i' '$($ds.Tables[1].Rows[$i][0])

Edit: Using double quotes might also be clearer since you can include the expressions within the quoted string:

编辑：使用双引号可能也更清楚，因为您可以在引用的字符串中包含表达式：

write-host "value is : $i $($ds.Tables[1].Rows[$i][0])"

#1