Object reference not set to an instance of an object.一般是什么原因造成?
解决方案 »
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声明了变量,但是没有赋值,仍然为null.用的时候就会报错.
{
return null;
}void ParseText()
{
string[] values = GetText().Split(',');
}
{
string sql = string.Format("SELECT * FROM {0} WHERE {1} = @{1} ", tableNamne, primaryKey); //这个我试过输出了正确
#if DEBUG
Console.Write("marshalColumn=" + marshalColumn + "!"); //marshalColumn是private property,这里输出 marshalColumn=!
#endif
if(marshalColumn != "")
{
fac = new OrderFormFac(connectionString, sql,marshalColumn,"^_.*");
OrderForm objOrderF = orderform as OrderForm;
fac.Save(objOrderF);
}
else
{
#if DEBUG
Console.Write("marshalColumn=" + marshalColumn + "!"); //这里没有输出
#endif fac = new OrderFormFac(connectionString,sql);
Dictionary objShopper = orderform as Dictionary;
#if DEBUG
Console.Write("orderform.shopper_id=" + objShopper["shopper_id"]);
#endif
fac.SaveAs(objShopper);
}
}然后错误信息Object reference not set to an instance of an object这么怎么回事?
OrderForm objOrderF = orderform as OrderForm; Dictionary objShopper = orderform as Dictionary; fac.Save(objOrderF|objShopper); 时可能objShopper = null。
if(obj... != null)fac.Save(obj...)
{
#if DEBUG
Console.Write("marshalColumn=" + marshalColumn + "!"); //这里没有输出
#endif这里就没有输出了,到不了下面的代码
{
connectionString = sConnectionString;
tableNamne = sTable;
primaryKey = sKey;
if(!Convert.IsDBNull(sProgID))
progID = sProgID;
else
progID = string.Empty; if(!Convert.IsDBNull(sMarshalColumn))
marshalColumn = sMarshalColumn;
else
marshalColumn = "";
if(!Convert.IsDBNull(sDateChanged))
dateChanged = sDateChanged;
else
dateChanged = string.Empty;
}
这个在InsertData之前调用了
marshalColumn = sMarshalColumn;
else
marshalColumn = "";直接改为:marshalColumn = sMarshalColumn;
{
connectionString = sConnectionString;
tableNamne = sTable;
primaryKey = sKey;
if(!Convert.IsDBNull(sProgID))
progID = sProgID;
else
progID = string.Empty; if(!Convert.IsDBNull(sMarshalColumn))
marshalColumn = sMarshalColumn;
else
marshalColumn = " ";
if(!Convert.IsDBNull(sDateChanged))
dateChanged = sDateChanged;
else
dateChanged = string.Empty;
}
这个在InsertData之前调用了