我试图为gridview页脚文本框获取自动ID填充，但每次运行时我都会获得对象的＆＃34; Not Referred Instance＆＃34;意思是方法找不到文本框，对吧？ 但我在其他方法中有相同的文本框，并且工作正常，它有什么不对？
以下是GridView的代码示例
<asp:GridView ID="GridView1" runat="server" BackColor="#CCCCCC" BorderColor="#999999" BorderStyle="Solid" BorderWidth="3px" CellPadding="4" CellSpacing="2" ForeColor="Black" AutoGenerateColumns="False" ShowFooter="True">
<Columns>
<asp:TemplateField HeaderText="ID UNIDAD">
<EditItemTemplate>
<asp:TextBox ID="TextBox1" runat="server" Text='<%# Bind("ID_UNIDAD") %>'></asp:TextBox>
</EditItemTemplate>
<FooterTemplate>
<asp:TextBox ID="txtAddID" runat="server" ></asp:TextBox>
</FooterTemplate>
<ItemTemplate>
<asp:Label ID="lbl_ID" runat="server" Text='<%# Bind("ID_UNIDAD") %>'></asp:Label>
</ItemTemplate>
</asp:TemplateField>
<asp:TemplateField HeaderText="UNIDAD">
<EditItemTemplate>
<asp:TextBox ID="TextBox2" runat="server" Text='<%# Bind("NOMBRE") %>'></asp:TextBox>
</EditItemTemplate>
<FooterTemplate>
<asp:TextBox ID="txtNombre" runat="server" ></asp:TextBox>
</FooterTemplate>
<ItemTemplate>
<asp:Label ID="lbl_Nombre" runat="server" Text='<%# Bind("NOMBRE") %>'></asp:Label>
</ItemTemplate>
</asp:TemplateField>
<asp:TemplateField HeaderText="FRACCIONES">
<EditItemTemplate>
<asp:CheckBox ID="TextBox3" runat="server" Checked='<%# Bind("FRACCIONES") %>'></asp:CheckBox>
</EditItemTemplate>
<FooterTemplate>
<asp:CheckBox ID="chkFraccion" runat="server" ></asp:CheckBox>
</FooterTemplate>
<ItemTemplate>
<asp:CheckBox ID="lbl_Fraccion" runat="server" Checked='<%# Bind("FRACCIONES") %>' ></asp:CheckBox>
</ItemTemplate>
</asp:TemplateField>
<asp:TemplateField HeaderText="CLAVE SAT">
<EditItemTemplate>
<asp:TextBox ID="TextBox4" runat="server" Text='<%# Bind("CLAVE_SAT") %>'></asp:TextBox>
</EditItemTemplate>
<FooterTemplate>
<asp:TextBox ID="txtClave" runat="server" ></asp:TextBox>
</FooterTemplate>
<ItemTemplate>
<asp:Label ID="lbl_Clave" runat="server" Text='<%# Bind("CLAVE_SAT") %>'></asp:Label>
</ItemTemplate>
</asp:TemplateField>
<asp:TemplateField>
<FooterTemplate>
<asp:ImageButton ID="Agregar" runat="server" ImageUrl="~/assets/iconos/add.ico" OnClick="Agregar_Click" />
</FooterTemplate>
</asp:TemplateField>
</Columns>
<FooterStyle BackColor="#CCCCCC" />
<HeaderStyle BackColor="Black" Font-Bold="True" ForeColor="White" />
<PagerStyle BackColor="#CCCCCC" ForeColor="Black" HorizontalAlign="Left" />
<RowStyle BackColor="White" />
<SelectedRowStyle BackColor="#000099" Font-Bold="True" ForeColor="White" />
<SortedAscendingCellStyle BackColor="#F1F1F1" />
<SortedAscendingHeaderStyle BackColor="#808080" />
<SortedDescendingCellStyle BackColor="#CAC9C9" />
<SortedDescendingHeaderStyle BackColor="#383838" />
</asp:GridView>
以下是在
后面的代码中绑定网格的代码示例using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Data;
using System.Data.SqlClient;
using System.Configuration;
using System.Web.UI.HtmlControls;
using System.Windows.Input;
public partial class Default2 : System.Web.UI.Page
{
SqlConnection con = new SqlConnection(ConfigurationManager.ConnectionStrings["Integral Database"].ToString());
string query;
string countid = " ";
SqlConnection connStr = new SqlConnection(ConfigurationManager.ConnectionStrings["Integral Database"].ToString());
string connStrr = ConfigurationManager.ConnectionStrings["Integral Database"].ConnectionString;
protected void Page_Load(object sender, EventArgs e)
{
if (!IsPostBack)
llenagrid();
IncrementoID();
}
public void llenagrid()
{
DataTable table = new DataTable();
using (SqlConnection conn = new SqlConnection(connStrr))
{
string sql = "SELECT id_unidad, nombre, fracciones, clave_sat from unidades";
using (SqlCommand cmd = new SqlCommand(sql, conn))
{
using (SqlDataAdapter ad = new SqlDataAdapter(cmd))
{
ad.Fill(table);
}
}
}
IncrementoID();
GridView1.DataSource = table;
GridView1.DataBind();
}
protected void Agregar_Click(object sender, ImageClickEventArgs e)
{
connStr.Open();
GridViewRow row = GridView1.FooterRow;
TextBox txtNombre = (TextBox)row.FindControl("txtNombre");
string str = "select count(nombre) from unidades where nombre like '"+txtNombre.Text+ "'";
SqlCommand com = new SqlCommand(str,connStr);
int count = Convert.ToInt32(com.ExecuteScalar());
connStr.Close();
if (count > 0)
{
string script = "alert('Este Nombre ya Existe.','Atención');";
ScriptManager.RegisterStartupScript(this, this.GetType(), "testScript", script, true);
}
else
{
connStr.Open();
TextBox txtID = (TextBox)row.FindControl("txtAddID");
CheckBox chkFracc = (CheckBox)row.FindControl("chkFraccion");
TextBox txtClave = (TextBox)row.FindControl("txtClave");
string ID = txtID.Text;
string Nombre = txtNombre.Text;
bool Fracc = chkFracc.Checked;
string clave = txtClave.Text;
string query2 = "Insert into unidades values('" + ID + "','" + Nombre + "','" + Fracc + "','" + clave + "')";
SqlCommand cmd2 = new SqlCommand(query2, connStr);
cmd2.ExecuteNonQuery();
connStr.Close();
llenagrid();
IncrementoID();
}
}
public void IncrementoID()
{
//query = "select Count(id_unidad) from unidades";
//con.Open();
//SqlCommand cmd = new SqlCommand(query, con);
//string cid = cmd.ExecuteScalar().ToString();
//con.Close();
//TextBox ID = (TextBox)GridView1.FooterRow.FindControl("txtAddID");
//ID.Text = countid + (int.Parse(cid) + 1);
//ID.ReadOnly = true;
con.Open();
SqlCommand cmd = new SqlCommand("select MAX (CAST( ID_UNIDAD as INT)) from unidades",con);
SqlDataReader rd = cmd.ExecuteReader();
TextBox txtID = ((TextBox)GridView1.FooterRow.FindControl("txtAddID"));
if (rd.Read())
{
string Value = rd[0].ToString();
if (Value == "")
{
txtID.Text = "1";
}
else
{
txtID.Text = rd[0].ToString();
txtID.Text = (Convert.ToInt64(txtID.Text) + 1).ToString();
}
}
con.Close();
}
}
正如您所看到的，在insert方法中它找到了gridview文本框（txtAddID），当我尝试在IncrementoID方法中使用相同的语法时，它不起作用。
答案 0 :(得分：0)
以下是方法llenagrid()中的问题，在绑定GridView之前，您试图访问Gridview中的控件（在方法IncrementoID内），所以它给出错误 Not Referred对象的实例表示尚未引用您尝试访问的对象。下面的代码示例可以帮助您：
public void llenagrid()
{
DataTable table = new DataTable();
using (SqlConnection conn = new SqlConnection(connStrr))
{
string sql = "SELECT id_unidad, nombre, fracciones, clave_sat from unidades";
using (SqlCommand cmd = new SqlCommand(sql, conn))
{
using (SqlDataAdapter ad = new SqlDataAdapter(cmd))
{
ad.Fill(table);
}
}
}
//IncrementoID(); // Remove the function call from here
GridView1.DataSource = table;
GridView1.DataBind();
IncrementoID(); // Call the function after GridView got binded.
}