C# 检查数据表中是否存在字符串/记录
声明：本页面是StackOverFlow热门问题的中英对照翻译，遵循CC BY-SA 4.0协议，如果您需要使用它，必须同样遵循CC BY-SA许可，注明原文地址和作者信息，同时你必须将它归于原作者（不是我）：StackOverFlow
原文地址: http://stackoverflow.com/questions/11961059/
Warning: these are provided under cc-by-sa 4.0 license. You are free to use/share it, But you must attribute it to the original authors (not me):
StackOverFlow
Check if String / Record exists in DataTable
提问by Andrew
I have a String and I need to check if any column "item_manuf_id" in DataTable dtPs.Rows equals to certain value
我有一个字符串，我需要检查 DataTable dtPs.Rows 中的任何列“item_manuf_id”是否等于某个值
I can loop over all Rows and compare
我可以遍历所有行并进行比较
String id = dtPs.Rows[number]["item_manuf_id"].ToString()
if ("some value".equals(id)) etc.
but I am wondering if there is any way to check if DataTablecontains the record
但我想知道是否有任何方法可以检查是否DataTable包含记录
采纳答案by Orn Kristjansson
Something like this
像这样的东西
string find = "item_manuf_id = 'some value'";
DataRow[] foundRows = table.Select(find);
回答by aleroot
回答by Sani Singh Huttunen
Use the Findmethod if item_manuf_idis a primary key:
如果是主键，则使用Find方法item_manuf_id：
var result = dtPs.Rows.Find("some value");
If you only want to know if the value is in there then use the Containsmethod.
如果您只想知道该值是否在其中，请使用Contains方法。
if (dtPs.Rows.Contains("some value"))
{
...
}
Primary key restriction applies to Containsaswell.
主键限制也适用于Contains。
回答by Kirk
You can loop over each row of the DataTableand check the value.
您可以遍历 的每一行DataTable并检查值。
I'm a big fan of using a foreachloop when using IEnumerables. Makes it very simple and clean to look at or process each row
我非常喜欢在使用s时使用foreach循环IEnumerable。使查看或处理每一行变得非常简单和干净
DataTable dtPs = // ... initialize your DataTable
foreach (DataRow dr in dtPs.Rows)
{
if (dr["item_manuf_id"].ToString() == "some value")
{
// do your deed
}
}
Alternatively you can use a PrimaryKeyfor your DataTable. This helps in various ways, but you often need to define one before you can use it.
或者，您可以PrimaryKey为您的DataTable. 这在很多方面都有帮助，但您通常需要先定义一个，然后才能使用它。
An example of using one if at http://msdn.microsoft.com/en-us/library/z24kefs8(v=vs.80).aspx
在http://msdn.microsoft.com/en-us/library/z24kefs8(v=vs.80).aspx上使用 if 的示例
DataTable workTable = new DataTable("Customers");
// set constraints on the primary key
DataColumn workCol = workTable.Columns.Add("CustID", typeof(Int32));
workCol.AllowDBNull = false;
workCol.Unique = true;
workTable.Columns.Add("CustLName", typeof(String));
workTable.Columns.Add("CustFName", typeof(String));
workTable.Columns.Add("Purchases", typeof(Double));
// set primary key
workTable.PrimaryKey = new DataColumn[] { workTable.Columns["CustID"] };
Once you have a primary key defined and data populated, you can use the Find(...)method to get the rows that match your primary key.
一旦定义了主键并填充了数据，就可以使用Find(...)方法获取与主键匹配的行。
Take a look at http://msdn.microsoft.com/en-us/library/y06xa2h1(v=vs.80).aspx
看看http://msdn.microsoft.com/en-us/library/y06xa2h1(v=vs.80).aspx
DataRow drFound = dtPs.Rows.Find("some value");
if (drFound["item_manuf_id"].ToString() == "some value")
{
// do your deed
}
Finally, you can use the Select()method to find data within a DataTablealso found at at http://msdn.microsoft.com/en-us/library/y06xa2h1(v=vs.80).aspx.
最后，您可以使用Select()方法DataTable在http://msdn.microsoft.com/en-us/library/y06xa2h1(v=vs.80).aspx 中找到的数据中查找数据。
String sExpression = "item_manuf_id == 'some value'";
DataRow[] drFound;
drFound = dtPs.Select(sExpression);
foreach (DataRow dr in drFound)
{
// do you deed. Each record here was already found to match your criteria
}
