Question

C#编程中怎样解决未将对象引用设置到对象的实例的问题 DataRow dr = dt.Rows.Find(txtName.Text);出错了

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;
using System.Data.SqlClient;

namespace 修改
{

public partial class Form1 : Form
{
public Form1()
{
InitializeComponent();

}
DataSet ds = new DataSet();
SqlDataAdapter sda;
DataRow dr;
private void Form1_Load(object sender, EventArgs e)
{
this.contactTableAdapter.Fill(this.通讯录DataSet.Contact);
SqlConnection con = new SqlConnection("server=localHost;database=通讯录;integrated security =true");
con.Open();
SqlCommand cmd = new SqlCommand("select * from Contact_Command ", con);
sda = new SqlDataAdapter();
sda.SelectCommand = cmd;

sda.Fill(ds, "Contact");
dataGridView1.DataSource = ds.Tables[0];

}

private void dataGridView1_CellClick(object sender, DataGridViewCellEventArgs e)
{

txtName.Text=dataGridView1.SelectedCells[0].Value.ToString();
txtBirthday.Text=dataGridView1.SelectedCells[1].Value.ToString();
txtPhone.Text=dataGridView1.SelectedCells[2].Value.ToString();
txtMail.Text=dataGridView1.SelectedCells[3].Value.ToString();
txtAddress.Text=dataGridView1.SelectedCells[4].Value.ToString();

}

private void button1_Click(object sender, EventArgs e)
{

DataTable dt = ds.Tables["Contact"];
SqlDataAdapter sda = new SqlDataAdapter();
// sda.FillSchema(dt,SchemaType.Mapped);
DataRow dr = dt.Rows.Find(txtName.Text);

dr["姓名"] = this.txtName.Text.Trim();
dr["生日"] = this .txtBirthday.Text.Trim();
dr["电话"] = this.txtPhone.Text.Trim();
dr["邮箱"] = this.txtMail.Text.Trim();
dr["地址"] = this.txtAddress.Text.Trim();

SqlCommandBuilder cmdbuilder=new SqlCommandBuilder(sda);
sda.Update(dt);

}

}
}

Answer 1

如果dr不是空的话，看一下txtName.Text的值，有可能是这个值有问题，导致找不到相应的数据列。

追问

具体的该如何做呢？谢谢！

追答

DataRow dr = dt.Rows.Find(txtName.Text);这句打个断点，看一下就行了

Answer 2

没有找到指定的行

Answer 3

没找到指定的主键行。

追问

要怎么解决呢？我不太懂 谢谢