Question

当我选择datagrid1时，它会显示错误

object reference not set

请帮我解决。我是wpf的新手。

 private void dataGrid1_SelectedCellsChanged(object sender, SelectedCellsChangedEventArgs e)
        {
            if (this.dataGrid1.SelectedItems == null || this.dataGrid1.SelectedItems.Count <= 0) return;
            this.db = new DbAccess();
            string str = this.dataGrid1.SelectedCells[0].Item.ToString();
            DataTable dataTable =
                this.db.DataTab(
                    @"SELECT [SeriesNo], [SeriesDescription], [Instances] 
                      FROM   [Roamani].[dbo].[View_Study123]
                      WHERE[StudyUID] = '" + str +"'");
            string[] strArray = new string[4];
            if (dataTable.Rows.Count > 0)
            {
                strArray[0] = str;
                strArray[1] = dataTable.Rows[0]["SeriesNo"].ToString();
                strArray[2] = dataTable.Rows[0]["SeriesDescription"].ToString();
                strArray[3] = dataTable.Rows[0]["Instances"].ToString();
            }
        }

Answer 1

用下面提到的方法替换你的方法并更改conncetion字符串。

 public DataTable DataTab(string query)
    {
        string conncetion = "Data Source=(local);Initial Catalog=Temp;User ID=sa;Password=sa123*";
        SqlConnection cnn = new SqlConnection(conncetion);

        string str = string.Empty;
        SqlCommand cmd = new SqlCommand();
        cmd.CommandType = CommandType.Text;
        cmd.Connection = cnn;
        if (cnn.State == ConnectionState.Closed)
            cnn.Open();

        DataTable dataTable = new DataTable(); 
        SqlDataAdapter adp = new SqlDataAdapter(query, cnn);
        adp.Fill(dataTable);
        return dataTable;

    }

仍然是null，然后尝试使用此查询

 @"SELECT [SeriesNo], [SeriesDescription], [Instances] 
                  FROM   [View_Study123].[dbo].[Roamani]
                  WHERE[StudyUID] = '" + str +"'");

此处View_study123是您的数据库名称，Romani是您的表名

对象引用未设置错误

1 个答案: