如何在再写之前查找记录是否存在 [英] How to find whether record exist before write again

问题描述

我正在尝试转换文本文件，读取文本文件并加载

将它们变为变量。



现在我想看到是否记录存在再写入之前



这是正确的方式看记录退出

DataRow [] foundRows;

foundRows = this.timeattDataSet.Tables [Data]。选择（Token_no = @cToken和Date = @datetime and Time = @cTime）;



Ajith



（我是c＃的新手）



我的尝试：

I am trying to convert text file, read the text file and loaded
them to variables.

now I want to see whether record exist before write again

Is this correct way see record exit
DataRow[] foundRows;
foundRows = this.timeattDataSet.Tables["Data"].Select("Token_no= @cToken and Date = @datetime and Time = @cTime");

Ajith

(I am new to c#)

What I have tried:

Token1 = str.ToString().Substring(0, 9).Trim();
cToken2 = '5' + cToken1.PadLeft(5, '0');
cToken = cToken2.Substring(0, 6);
cDate = str.ToString().Substring(10, 10);
cTime = str.ToString().Substring(21, 2) + str.ToString().Substring(24, 2);
cIdno = str.ToString().Substring(30, 1);
datetime = Convert.ToDateTime(cDate);

DataRow[] foundRows;
foundRows = this.timeattDataSet.Tables["Data"].Select("Token_no= @cToken and Date = @datetime and Time = @cTime");

推荐答案

使用LINQ：

Use LINQ:

bool rowExists = timeattDataSet.Tables["Data"].AsEnumerable()
    .Any(row => string.Equals(row.Field<string>("Token_no"), cToken, StringComparison.OrdinalIgnoreCase) && row.Field<DateTime>("Date") == datetime);

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