DataTable.Compute找不到coloumn [英] DataTable.Compute Cannot find coloumn

问题描述

我正在尝试从表empLoan WHERE empID = empID变量中计算列loanGiven的结果。以下是代码

I am trying to compute results from a column loanGiven from a table empLoan WHERE empID = empID variable. Following is the code

sumObject = this.shahiemsDataSet.empLoan.Compute("SUM(loanGiven)", "empID = " + empID)

变量empID从datagridview单元格中获取值。（工作正常）



我收到以下错误'找不到Coloumn [EMP005]'。



是的，记录存在于数据库中。

是的我没有过滤器检查过。 （它工作正常）。

The variable empID gets value from datagridview cells.(Works fine)

I get the following error 'Cannot find Coloumn[EMP005]'.

Yes the record exists in the database.
Yes I have checked without filter. (It works fine).

推荐答案

找到解决方案。

Found the solution.

sumObject = this.shahiemsDataSet.empLoan.Compute("SUM(loanGiven)", "empID = ' " + empID"'")

请参阅 https://msdn.microsoft.com/en-us/library/system.data.datatable.compute%28v=vs.110%29.aspx [<一个href =https://msdn.microsoft.com/en-us/library/system.data.datatable.compute%28v=vs.110%29.aspx\"target =_ blanktitle =New Window> ^ ]

Please see https://msdn.microsoft.com/en-us/library/system.data.datatable.compute%28v=vs.110%29.aspx[^]

public Object Compute(
    string expression,
    string filter
)

这意味着你必须将两个参数作为字符串传递但是你正在传递字符串，字符串+ int

it means you have to pass both parameter as string But you are passing string, string+int

public Object Compute(
    string ,
    string +int
)

你的第二个参数也应该是字符串类型



empID =+ empID +'

your second parameter also should be string type as

"empID = " + empID + "'"

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