使用 where 子句过滤数据表行 [英] Filtering a datatable row using a where clause

问题描述

我有一个从数据集中提取的数据表.在 DataTable 中，我想使用 Where 子句返回特定行.我查看了如何使用两个变量值从数据表中选择一行?"但出现错误p><块引用>

"不能将类型'System.Data.DataRow[]'隐式转换为'System.Data.DataRow'"

我搜索了谷歌，但找不到解决方案.

我的代码是:

mySqlDataAdapter.Fill(myDataSet);数据表 dtTable = myDataSet.Tables[0];DataRow dr = dtTable.Select("VendorID = " + Session["VendorId"].ToString());

我该如何解决这个问题?

解决方案

选择 即使您的查询只选择一行，DataTable 的方法也会返回一个 DataRow 数组

DataRow[] dr = dtTable.Select("VendorID = " + Session["VendorId"].ToString());

然后，如果您真的只希望一行，您可以轻松获取预期的行来检查数组的长度.在这种情况下，我认为实际上不需要花哨的 Enumerable 扩展方法

if(dr.Length > 0){字符串 avalue = dr[0]["AColumnName"].ToString();...}

I have a DataTable that I am pulling from a DataSet. From the DataTable, I want to use the Where clause to return a particular row. I looked at "How can I select a row from a datatable using two variable values?" but I get an error

"Cannot implicitly convert type 'System.Data.DataRow[]' to 'System.Data.DataRow'"

I searched google, but could not find a solution.

My code is:

mySqlDataAdapter.Fill(myDataSet);

DataTable dtTable = myDataSet.Tables[0];
DataRow dr = dtTable.Select("VendorID = " + Session["VendorId"].ToString());

How can I resolve this?

解决方案

The Select method of a DataTable returns an array of DataRow even if your query selects only one row

DataRow[] dr = dtTable.Select("VendorID = " + Session["VendorId"].ToString());

Then, if you really expects just one row, you could easily grab the expected row checking for the length of the array. In this case it is my opinion that no fancy Enumerable extension methods are really needed

if(dr.Length > 0)
{
    string avalue = dr[0]["AColumnName"].ToString();
    ...
}

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