private void button1_Click(object sender, EventArgs e)
{
//button1.Enabled = true;
textBox1.Enabled = true;
textBox2.Enabled = true;
comboBox1.Enabled = true; textBox1.Text = "";
textBox2.Text = "";
comboBox1.Text = ""; int ctr, len;
string codeval;
dt = aDataSet.Tables["student"]; len = dt.Rows.Count - 1;
dr = dt.Rows[len];
code = dr["sid"].ToString();
codeval = code.Substring(1, 3);
ctr = Convert.ToInt32(codeval); if ((ctr >= 1) && (ctr < 9))
{
ctr = ctr + 1;
textBox1.Text = "C00" + ctr;
}
else if ((ctr >= 9) && (ctr < 99))
{
ctr = ctr + 1;
textBox1.Text = "C0" + ctr;
}
else if (ctr >= 99)
{
ctr = ctr + 1;
textBox1.Text = "C" + ctr;
}
button1.Enabled = false;
button2.Enabled = true;
//button3.Enabled = false;
} private void button2_Click(object sender, EventArgs e)
{
dt = aDataSet.Tables["student"];
dr = dt.NewRow();
dr[0] = textBox1.Text;
dr[1] = textBox2.Text;
dr[2] = comboBox1.Text; dt.Rows.Add(dr);
studentTableAdapter.Update(aDataSet);
textBox1.Text = System.Convert.ToString(dr[0]); textBox1.Enabled = false;
textBox2.Enabled = false;
comboBox1.Enabled = false;
//this.studTableAdapter.Fill(this.aDataSet.stud);
this.studentTableAdapter.Fill(this.aDataSet.student); button1.Enabled = true;
button2.Enabled = false; }
{
//button1.Enabled = true;
textBox1.Enabled = true;
textBox2.Enabled = true;
comboBox1.Enabled = true; textBox1.Text = "";
textBox2.Text = "";
comboBox1.Text = ""; int ctr, len;
string codeval;
dt = aDataSet.Tables["student"]; len = dt.Rows.Count - 1;
dr = dt.Rows[len];
code = dr["sid"].ToString();
codeval = code.Substring(1, 3);
ctr = Convert.ToInt32(codeval); if ((ctr >= 1) && (ctr < 9))
{
ctr = ctr + 1;
textBox1.Text = "C00" + ctr;
}
else if ((ctr >= 9) && (ctr < 99))
{
ctr = ctr + 1;
textBox1.Text = "C0" + ctr;
}
else if (ctr >= 99)
{
ctr = ctr + 1;
textBox1.Text = "C" + ctr;
}
button1.Enabled = false;
button2.Enabled = true;
//button3.Enabled = false;
} private void button2_Click(object sender, EventArgs e)
{
dt = aDataSet.Tables["student"];
dr = dt.NewRow();
dr[0] = textBox1.Text;
dr[1] = textBox2.Text;
dr[2] = comboBox1.Text; dt.Rows.Add(dr);
studentTableAdapter.Update(aDataSet);
textBox1.Text = System.Convert.ToString(dr[0]); textBox1.Enabled = false;
textBox2.Enabled = false;
comboBox1.Enabled = false;
//this.studTableAdapter.Fill(this.aDataSet.stud);
this.studentTableAdapter.Fill(this.aDataSet.student); button1.Enabled = true;
button2.Enabled = false; }
dr = dt.Rows[len]; //获取最后一行的DataReader
dr = dt.Rows[len]; //把最后一行的的内容赋给dr,有可能是dataReader或DataRow,看你的代码
dr = dt.Rows[len]; 获取dt中最后一行dr
len就是数据集dt的所有行rows的数量。
dr是一个数据行,赋值的是dt的最后一行数据的引用。
dr = dt.Rows[len]; //把最后一行赋值给一个DATAROW
由于索引从0开始,所以最后一行的索引号就是Rows.Count-1
补充一下:
dt有多少行,第一行算一哦,从一数到10,就是十条
如果要引用其中(数组)某条,索引从0算起哦,也就是第一行成0行罗,从0数到9就是十条记录哦
不说了,再说我又晕了
想当初我刚开始搞C语言的时候,这个问题模糊好久
现在C语系包括跟C语系有亲戚关系的也是如此
dr = dt.Rows[len];//最后一行
dr = dt.Rows[len]; //获取最后一行的DataReader
dr = dt.Rows[len]; //这里的类型是DataRow不是DataReader