Gridview中的Dropdroplist绑定 [英] Dropdroplist binding in Gridview

问题描述

我在网格edititemtemplate中的dropdownlist上添加了内容，当我将.cs文件中的数据与事件rowdataboud绑定在一起时，出现错误

Hi,
i added on dropdownlist in grid edititemtemplate, when i am binding the data in .cs file with the event rowdataboud then i got the error

System.NullReferenceException: Object reference not set to an instance of an object.

这是我的示例CS代码

here is my sample cs code

protected void gvTestType_RowDataBound(object sender, GridViewRowEventArgs e)
        {
            if (e.Row.RowType == DataControlRowType.DataRow)
            {
                DropDownList ddl = (DropDownList)e.Row.FindControl("ddlStatus");
               DataSet ds = new DataSet();
               StatusBll sBl = new StatusBll();
                ds = sBl.SelectStatusDetails();
                ddl.DataTextField = "Description";//the source of your dropdown
                ddl.DataValueField = "StatusId";
                ddl.DataSource = ds.Tables["Status"];
                ddl.DataBind();
            }
        }

推荐答案

可能是您的

sBl.SelectStatusDetails()

试图从空值中获取变量.

或

tries to get a variable from something that is null.

Or

ds.Tables["Status"]

不存在...

对象引用未设置为对象的实例

当您尝试使用属性或调用对象的方法为null时，会发生此错误.更多详细信息:此处 [

Object reference not set to an instance of an object

This error happens when you try to use a property or call a method of an object that is null. More details: here[^]

A simple use of Visual studio DEBUGGER can tell you the object because of which it is happening. Just look at the stack trace and put a debugger on that line. Check the objects of that line and see if any one is null and you are trying to use that objects property. Handle the same.

Based on the code snippet shared, potential places:

DropDownList ddl = (DropDownList)e.Row.FindControl("ddlStatus"); //ddlStatus was not found and explicit cast threw an error

ds = sBl.SelectStatusDetails(); // ds returned is null or empty, assuming no error in method called!

ddl.DataSource = ds.Tables["Status"]; // there is no table named 'Status' in the dataset ds

检查，查找并修复它.

Check, find and fix it.

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