我如何解决这个错误“system.invalidcastexception无法将'system.int64'类型的对象强制转换为'system.string'" [英] How do i solve this error "system.invalidcastexception unable to cast object of type 'system.int64' to type 'system.string' "

问题描述

protected string gridValueChopping(object dataItem, string dataField, int iSize)
    {
        string gridValue = (string)DataBinder.Eval(dataItem, dataField);
        string output = string.Empty;
        if (gridValue.Length > iSize)
        {
            output = ((string)DataBinder.Eval(dataItem, dataField)).Substring(0, iSize - 3);
            output = output + "...";
        }
        else
        {
            output = (string)DataBinder.Eval(dataItem, dataField).ToString();
        }
        return output;
    }

我得到了系统.invalidcastexception无法将'system.int64'类型的对象强制转换为'system.string'在上面提到的代码的以下行中出错 -



string gridValue =（字符串）DataBinder.Eval（dataItem，dataField）;





我可以为此获得解决方案吗？



我尝试了什么：

I am getting the "system.invalidcastexception unable to cast object of type 'system.int64' to type 'system.string'"error in the following line of the above mentioned code -

string gridValue = (string)DataBinder.Eval(dataItem, dataField);


can I get a solution for this?

What I have tried:

string gridValue = (string)DataBinder.Eval(dataItem, dataField);

我改变了这一行，

I changed this line as,

string gridValue = (string)DataBinder.Eval(dataItem, dataField).ToString;

但即使这样，错误也会重复..

but even then the error repeats..

推荐答案

另一种选择：

Another alternative:

string gridValue = DataBinder.Eval(dataItem, dataField, "{0}");

另外，请不要 Eval 多次相同的值;使用从第一次调用 Eval 中检索到的值：

Also, don't Eval the same value multiple times; use the value retrieved from the first call to Eval instead:

protected string gridValueChopping(object dataItem, string dataField, int iSize)
{
    string gridValue = DataBinder.Eval(dataItem, dataField, "{0}");
    string output;
    
    if (gridValue.Length > iSize)
    {
        output = gridValue.Substring(0, iSize - 3);
        output = output + "...";
    }
    else
    {
        output = gridValue;
    }
    
    return output;
}

long longValue = (long)DataBinder.Eval(dataItem, dataField);
string gridValue = longValue.ToString();

应该这样做，或者至少应该允许更好地了解问题所在。

should do it, or at least should allow to better understand where the problem lies.

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