null - NullReferenceException Was Unhandled C# (Using BindingList) -

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• what nullreferenceexception, , how fix it? 29 answers

i trying redevelop program , can't figure out causes error.

additional info: object reference not set instance of object.

private void setdatasource(bindinglist<listobject> list)         {             if(this.datagridview1.invokerequired)             {                 setdscallback method = new setdscallback(this.setdatasource);                 base.invoke(method, new object[] { list }); <-- error here             }             else             {                 this.datagridview1.datasource = null;                 this.datagridview1.datasource = list;                 this.datagridview1.columns["ip"].headertext = "external ip";                 this.datagridview1.columns["macaddress"].headertext = "mac address";                 this.datagridview1.columns["ipsource"].headertext = "ip source";                 this.datagridview1.columns["ipdest"].headertext = "ip destination";                 this.datagridview1.columns["portsource"].headertext = "source port";                 this.datagridview1.columns["portdest"].headertext = "destination port";                 this.datagridview1.columns["protocol"].headertext = "protocol";                 this.datagridview1.columns["label"].headertext = "label";                 this.datagridview1.columns["country"].headertext = "country";                 this.datagridview1.columns["state"].headertext = "state";                 this.datagridview1.columns["city"].headertext = "city";                 this.datagridview1.columns["packetcount"].headertext = "packets";             }         } 

i willing send entire project if willing out. listobject class class of getters , setters.

put if, else block in if , check if(list!=null) , put if else block in it.

    private void setdatasource(bindinglist<listobject> list)         {           if(list!=null)            {             if(this.datagridview1.invokerequired)             {                 setdscallback method = new setdscallback(this.setdatasource);                 base.invoke(method, new object[] { list }); <-- error here             }             else             {                 this.datagridview1.datasource = null;                 this.datagridview1.datasource = list;                 this.datagridview1.columns["ip"].headertext = "external ip";                 this.datagridview1.columns["macaddress"].headertext = "mac address";                 this.datagridview1.columns["ipsource"].headertext = "ip source";                 this.datagridview1.columns["ipdest"].headertext = "ip destination";                 this.datagridview1.columns["portsource"].headertext = "source port";                 this.datagridview1.columns["portdest"].headertext = "destination port";                 this.datagridview1.columns["protocol"].headertext = "protocol";                 this.datagridview1.columns["label"].headertext = "label";                 this.datagridview1.columns["country"].headertext = "country";                 this.datagridview1.columns["state"].headertext = "state";                 this.datagridview1.columns["city"].headertext = "city";                 this.datagridview1.columns["packetcount"].headertext = "packets";             }          }          else          {           //handle if list null          }         }